text: /*!
   * Casper is a navigation utility for PhantomJS.
   *
   * Documentation: http://casperjs.org/
   * Repository:    http://github.com/n1k0/casperjs
   *
   * Copyright (c) 2011-2012 Nicolas Perriault
   *
   * Part of source code is Copyright Joyent, Inc. and other Node contributors.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   *
   */
  
  /*global CasperError, console, exports, phantom, __utils__, patchRequire, require:true*/
  
  var require = patchRequire(require);
  var colorizer = require('colorizer');
  var events = require('events');
  var fs = require('fs');
  var http = require('http');
  var mouse = require('mouse');
  var pagestack = require('pagestack');
  var qs = require('querystring');
  var tester = require('tester');
  var utils = require('utils');
  var f = utils.format;
  
  
  var defaultUserAgent = phantom.defaultPageSettings.userAgent
      .replace(/(PhantomJS|SlimerJS)/, f("CasperJS/%s", phantom.casperVersion) + '+$&');
  
  exports.create = function create(options) {
      "use strict";
      // This is a bit of a hack to check if one is trying to override the preconfigured
      // casper instance from within a test environment.
      if (phantom.casperTest && window.casper) {
          console.error("Fatal: you can't override the preconfigured casper instance in a test environment.");
          console.error("Docs: http://docs.casperjs.org/en/latest/testing.html#test-command-args-and-options");
          phantom.exit(1);
      }
      return new Casper(options);
  };
  
  /**
   * Shortcut to build an XPath selector object.
   *
   * @param  String  expression  The XPath expression
   * @return Object
   * @see    http://casperjs.org/selectors.html
   */
  function selectXPath(expression) {
      "use strict";
      return {
          type: 'xpath',
          path: expression,
          toString: function() {
              return this.type + ' selector: ' + this.path;
          }
      };
  }
  exports.selectXPath = selectXPath;
  
  /**
   * Main Casper object.
   *
   * @param  Object  options  Casper options
   */
  var Casper = function Casper(options) {
      "use strict";
      /*jshint maxstatements:40*/
      // init & checks
      if (!(this instanceof Casper)) {
          return new Casper(options);
      }
      // default options
      this.defaults = {
          clientScripts:       [],
          colorizerType:       'Colorizer',
          exitOnError:         true,
          logLevel:            "error",
          httpStatusHandlers:  {},
          safeLogs:            true,
          onAlert:             null,
          onDie:               null,
          onError:             null,
          onLoadError:         null,
          onPageInitialized:   null,
          onResourceReceived:  null,
          onResourceRequested: null,
          onRunComplete:       function _onRunComplete() {
              this.exit();
          },
          onStepComplete:      null,
          onStepTimeout:       function _onStepTimeout(timeout, stepNum) {
              this.die("Maximum step execution timeout exceeded for step " + stepNum);
          },
          onTimeout:           function _onTimeout(timeout) {
              this.die(f("Script timeout of %dms reached, exiting.", timeout));
          },
          onWaitTimeout:       function _onWaitTimeout(timeout) {
              this.die(f("Wait timeout of %dms expired, exiting.", timeout));
          },
          page:                null,
          pageSettings:        {
              localToRemoteUrlAccessEnabled: true,
              userAgent:                     defaultUserAgent
          },
          remoteScripts:       [],
          silentErrors:        false,
          stepTimeout:         null,
          timeout:             null,
          verbose:             false,
          retryTimeout:        20,
          waitTimeout:         5000,
          clipRect : null,
          viewportSize : null
      };
      // options
      this.options = utils.mergeObjects(this.defaults, options);
      // factories
      this.cli = phantom.casperArgs;
      this.options.logLevel = this.cli.get('log-level', this.options.logLevel);
      if (!this.options.verbose) {
          this.options.verbose = this.cli.has('direct') || this.cli.has('verbose');
      }
      this.colorizer = this.getColorizer();
      this.mouse = mouse.create(this);
      this.popups = pagestack.create();
      // properties
      this.checker = null;
      this.currentResponse = {};
      this.currentUrl = 'about:blank';
      this.currentHTTPStatus = null;
      this.history = [];
      this.loadInProgress = false;
      this.navigationRequested = false;
      this.browserInitializing = false;
      this.logFormats = {};
      this.logLevels = ["debug", "info", "warning", "error"];
      this.logStyles = {
          debug:   'INFO',
          info:    'PARAMETER',
          warning: 'COMMENT',
          error:   'ERROR'
      };
      this.page = null;
      this.pendingWait = false;
      this.requestUrl = 'about:blank';
      this.resources = [];
      this.result = {
          log:    [],
          status: "success",
          time:   0
      };
      this.started = false;
      this.step = -1;
      this.steps = [];
      this.waiters = [];
      this._test = undefined;
      this.__defineGetter__('test', function() {
          if (!phantom.casperTest) {
              throw new CasperError('casper.test property is only available using the `casperjs test` command');
          }
          if (!utils.isObject(this._test)) {
              this._test = tester.create(this);
          }
          return this._test;
      });
  
      // init phantomjs error handler
      this.initErrorHandler();
  
      this.on('error', function(msg, backtrace) {
          var c = this.getColorizer();
          var match = /^(.*): __mod_error(.*):: (.*)/.exec(msg);
          var notices = [];
          if (match && match.length === 4) {
              notices.push('  in module ' + match[2]);
              msg = match[3];
          }
          console.error(c.colorize(msg, 'RED_BAR', 80));
          notices.forEach(function(notice) {
              console.error(c.colorize(notice, 'COMMENT'));
          });
          (backtrace || []).forEach(function(item) {
              var message = fs.absolute(item.file) + ":" + c.colorize(item.line, "COMMENT");
              if (item['function']) {
                  message += " in " + c.colorize(item['function'], "PARAMETER");
              }
              console.error("  " + message);
          });
      });
  
      // deprecated feature event handler
      this.on('deprecated', function onDeprecated(message) {
          this.warn('[deprecated] ' + message);
      });
  
      // dispatching an event when instance has been constructed
      this.emit('init');
  
      // deprecated direct option
      if (this.cli.has('direct')) {
          this.emit("deprecated", "--direct option has been deprecated since 1.1; you should use --verbose instead.")
      }
  };
  
  // Casper class is an EventEmitter
  utils.inherits(Casper, events.EventEmitter);
  
  /**
   * Go a step back in browser's history
   *
   * @return Casper
   */
  Casper.prototype.back = function back() {
      "use strict";
      this.checkStarted();
      return this.then(function() {
          this.emit('back');
          this.page.goBack();
      });
  };
  
  /**
   * Encodes a resource using the base64 algorithm synchronously using
   * client-side XMLHttpRequest.
   *
   * NOTE: we cannot use window.btoa() for some strange reasons here.
   *
   * @param  String  url     The url to download
   * @param  String  method  The method to use, optional: default GET
   * @param  String  data    The data to send, optional
   * @return string          Base64 encoded result
   */
  Casper.prototype.base64encode = function base64encode(url, method, data) {
      "use strict";
      return this.callUtils("getBase64", url, method, data);
  };
  
  /**
   * Bypasses `nb` steps.
   *
   * @param  Integer  nb  Number of steps to bypass
   */
  Casper.prototype.bypass = function bypass(nb) {
      "use strict";
      var step = this.step,
          steps = this.steps,
          last = steps.length;
      this.checkStarted();
      this.step = Math.min(step + nb, last);
      return this;
  };
  
  /**
   * Invokes a client side utils object method within the remote page, with arguments.
   *
   * @param  {String}   method  Method name
   * @return {...args}          Arguments
   * @return {Mixed}
   * @throws {CasperError}      If invokation failed.
   */
  Casper.prototype.callUtils = function callUtils(method) {
      "use strict";
      var args = [].slice.call(arguments, 1);
      var result = this.evaluate(function(method, args) {
          return __utils__.__call(method, args);
      }, method, args);
      if (utils.isObject(result) && result.__isCallError) {
          throw new CasperError(f("callUtils(%s) with args %s thrown an error: %s",
                                method, args, result.message));
      }
      return result;
  };
  
  /**
   * Proxy method for WebPage#render. Adds a clipRect parameter for
   * automatically set page clipRect setting values and sets it back once
   * done. If the cliprect parameter is omitted, the full page viewport
   * area will be rendered.
   *
   * @param  String  targetFile  A target filename
   * @param  mixed   clipRect    An optional clipRect object (optional)
   * @return Casper
   */
  Casper.prototype.capture = function capture(targetFile, clipRect, imgOptions) {
      "use strict";
      /*jshint maxstatements:20*/
      this.checkStarted();
      var previousClipRect;
      targetFile = fs.absolute(targetFile);
      if (clipRect) {
          if (!utils.isClipRect(clipRect)) {
              throw new CasperError("clipRect must be a valid ClipRect object.");
          }
          previousClipRect = this.page.clipRect;
          this.page.clipRect = clipRect;
          this.log(f("Capturing page to %s with clipRect %s", targetFile, JSON.stringify(clipRect)), "debug");
      } else {
          this.log(f("Capturing page to %s", targetFile), "debug");
      }
      if (!this.page.render(this.filter('capture.target_filename', targetFile) || targetFile, imgOptions)) {
          this.log(f("Failed to save screenshot to %s; please check permissions", targetFile), "error");
      } else {
          this.log(f("Capture saved to %s", targetFile), "info");
          this.emit('capture.saved', targetFile);
      }
      if (previousClipRect) {
          this.page.clipRect = previousClipRect;
      }
      return this;
  };
  
  /**
   * Returns a Base64 representation of a binary image capture of the current
   * page, or an area within the page, in a given format.
   *
   * Supported image formats are `bmp`, `jpg`, `jpeg`, `png`, `ppm`, `tiff`,
   * `xbm` and `xpm`.
   *
   * @param  String                   format    The image format
   * @param  String|Object|undefined  selector  DOM CSS3/XPath selector or clipRect object (optional)
   * @return Casper
   */
  Casper.prototype.captureBase64 = function captureBase64(format, area) {
      "use strict";
      /*jshint maxstatements:20*/
      this.checkStarted();
      var base64, previousClipRect, formats = ['bmp', 'jpg', 'jpeg', 'png', 'ppm', 'tiff', 'xbm', 'xpm'];
      if (formats.indexOf(format.toLowerCase()) === -1) {
          throw new CasperError(f('Unsupported format "%s"', format));
      }
      if (utils.isClipRect(area)) {
          // if area is a clipRect object
          this.log(f("Capturing base64 %s representation of %s", format, utils.serialize(area)), "debug");
          previousClipRect = this.page.clipRect;
          this.page.clipRect = area;
          base64 = this.page.renderBase64(format);
      } else if (utils.isValidSelector(area)) {
          // if area is a selector string or object
          this.log(f("Capturing base64 %s representation of %s", format, area), "debug");
          base64 = this.captureBase64(format, this.getElementBounds(area));
      } else {
          // whole page capture
          this.log(f("Capturing base64 %s representation of page", format), "debug");
          base64 = this.page.renderBase64(format);
      }
      if (previousClipRect) {
          this.page.clipRect = previousClipRect;
      }
      return base64;
  };
  
  /**
   * Captures the page area matching the provided selector.
   *
   * @param  String  targetFile  Target destination file path.
   * @param  String  selector    DOM CSS3/XPath selector
   * @return Casper
   */
  Casper.prototype.captureSelector = function captureSelector(targetFile, selector, imgOptions) {
      "use strict";
      return this.capture(targetFile, this.getElementBounds(selector), imgOptions);
  };
  
  /**
   * Checks for any further navigation step to process.
   *
   * @param  Casper    self        A self reference
   * @param  function  onComplete  An options callback to apply on completion
   */
  Casper.prototype.checkStep = function checkStep(self, onComplete) {
      "use strict";
      if (self.pendingWait || self.loadInProgress || self.navigationRequested || self.browserInitializing) {
          return;
      }
      var step = self.steps[self.step++];
      if (utils.isFunction(step)) {
          return self.runStep(step);
      }
      self.result.time = new Date().getTime() - self.startTime;
      self.log(f("Done %s steps in %dms", self.steps.length, self.result.time), "info");
      clearInterval(self.checker);
      self.step -= 1;
      self.emit('run.complete');
      try {
          if (utils.isFunction(onComplete)) {
              onComplete.call(self, self);
          } else if (utils.isFunction(self.options.onRunComplete)) {
              self.options.onRunComplete.call(self, self);
          }
      } catch (error) {
          self.emit('complete.error', error);
          if (!self.options.silentErrors) {
              throw error;
          }
      }
  };
  
  /**
   * Checks if this instance is started.
   *
   * @return Boolean
   * @throws CasperError
   */
  Casper.prototype.checkStarted = function checkStarted() {
      "use strict";
      if (!this.started) {
          throw new CasperError(f("Casper is not started, can't execute `%s()`",
                                  checkStarted.caller.name));
      }
  };
  
  /**
   * Clears the current page execution environment context. Useful to avoid
   * having previously loaded DOM contents being still active (refs #34).
   *
   * Think of it as a way to stop javascript execution within the remote DOM
   * environment.
   *
   * @return Casper
   */
  Casper.prototype.clear = function clear() {
      "use strict";
      this.checkStarted();
      this.page.content = '';
      return this;
  };
  
  /**
   * Emulates a click on the element from the provided selector using the mouse
   * pointer, if possible.
   *
   * In case of success, `true` is returned, `false` otherwise.
   *
   * @param  String   selector  A DOM CSS3 compatible selector
   * @return Boolean
   */
  Casper.prototype.click = function click(selector) {
      "use strict";
      this.checkStarted();
      var success = this.mouseEvent('mousedown', selector) && this.mouseEvent('mouseup', selector);
      success = success && this.mouseEvent('click', selector);
      this.evaluate(function(selector) {
          var element = __utils__.findOne(selector);
          if (element) {
              element.focus();
          }
      }, selector);
      this.emit('click', selector);
      return success;
  };
  
  /**
   * Emulates a click on the element having `label` as innerText. The first
   * element matching this label will be selected, so use with caution.
   *
   * @param  String   label  Element innerText value
   * @param  String   tag    An element tag name (eg. `a` or `button`) (optional)
   * @return Boolean
   */
  Casper.prototype.clickLabel = function clickLabel(label, tag) {
      "use strict";
      this.checkStarted();
      tag = tag || "*";
      var escapedLabel = utils.quoteXPathAttributeString(label);
      var selector = selectXPath(f('//%s[text()=%s]', tag, escapedLabel));
      return this.click(selector);
  };
  
  /**
   * Configures HTTP authentication parameters. Will try parsing auth credentials from
   * the passed location first, then check for configured settings if any.
   *
   * @param  String  location  Requested url
   * @param  Object  settings  Request settings
   * @return Casper
   */
  Casper.prototype.configureHttpAuth = function configureHttpAuth(location, settings) {
      "use strict";
      var httpAuthMatch = location.match(/^https?:\/\/(.+):(.+)@/i);
      this.checkStarted();
      if (httpAuthMatch) {
          this.page.settings.userName = httpAuthMatch[1];
          this.page.settings.password = httpAuthMatch[2];
      } else if (utils.isObject(settings) && settings.username) {
          this.page.settings.userName = settings.username;
          this.page.settings.password = settings.password;
      } else {
          return;
      }
      this.emit('http.auth', this.page.settings.userName, this.page.settings.password);
      this.log("Setting HTTP authentication for user " + this.page.settings.userName, "info");
      return this;
  };
  
  /**
   * Creates a step definition.
   *
   * @param  Function  fn       The step function to call
   * @param  Object    options  Step options
   * @return Function  The final step function
   */
  Casper.prototype.createStep = function createStep(fn, options) {
      "use strict";
      if (!utils.isFunction(fn)) {
          throw new CasperError("createStep(): a step definition must be a function");
      }
      fn.options = utils.isObject(options) ? options : {};
      this.emit('step.created', fn);
      return fn;
  };
  
  /**
   * Logs the HTML code of the current page.
   *
   * @param  String   selector  A DOM CSS3/XPath selector (optional)
   * @param  Boolean  outer     Whether to fetch outer HTML contents (default: false)
   * @return Casper
   */
  Casper.prototype.debugHTML = function debugHTML(selector, outer) {
      "use strict";
      this.checkStarted();
      return this.echo(this.getHTML(selector, outer));
  };
  
  /**
   * Logs the textual contents of the current page.
   *
   * @return Casper
   */
  Casper.prototype.debugPage = function debugPage() {
      "use strict";
      this.checkStarted();
      this.echo(this.evaluate(function _evaluate() {
          return document.body.textContent || document.body.innerText;
      }));
      return this;
  };
  
  /**
   * Exit phantom on failure, with a logged error message.
   *
   * @param  String  message  An optional error message
   * @param  Number  status   An optional exit status code (must be > 0)
   * @return Casper
   */
  Casper.prototype.die = function die(message, status) {
      "use strict";
      this.result.status = "error";
      this.result.time = new Date().getTime() - this.startTime;
      if (!utils.isString(message) || !message.length) {
          message = "Suite explicitly interrupted without any message given.";
      }
      this.log(message, "error");
      this.echo(message, "ERROR");
      this.emit('die', message, status);
      if (utils.isFunction(this.options.onDie)) {
          this.options.onDie.call(this, this, message, status);
      }
      return this.exit(~~status > 0 ? ~~status : 1);
  };
  
  /**
   * Downloads a resource and saves it on the filesystem.
   *
   * @param  String  url         The url of the resource to download
   * @param  String  targetPath  The destination file path
   * @param  String  method      The HTTP method to use (default: GET)
   * @param  String  data        Optional data to pass performing the request
   * @return Casper
   */
  Casper.prototype.download = function download(url, targetPath, method, data) {
      "use strict";
      this.checkStarted();
      var cu = require('clientutils').create(utils.mergeObjects({}, this.options));
      try {
          fs.write(targetPath, cu.decode(this.base64encode(url, method, data)), 'wb');
          this.emit('downloaded.file', targetPath);
          this.log(f("Downloaded and saved resource in %s", targetPath));
      } catch (e) {
          this.log(f("Error while downloading %s to %s: %s", url, targetPath, e), "error");
      }
      return this;
  };
  
  /**
   * Iterates over the values of a provided array and execute a callback for each
   * item.
   *
   * @param  Array     array
   * @param  Function  fn     Callback: function(casper, item, index)
   * @return Casper
   */
  Casper.prototype.each = function each(array, fn) {
      "use strict";
      if (!utils.isArray(array)) {
          this.log("each() only works with arrays", "error");
          return this;
      }
      array.forEach(function _forEach(item, i) {
          fn.call(this, this, item, i);
      }, this);
      return this;
  };
  
  /**
   * Iterates over the values of a provided array and adds a step for each item.
   *
   * @param  Array     array
   * @param  Function  then   Step: function(response); item will be attached to response.data
   * @return Casper
   */
  Casper.prototype.eachThen = function each(array, then) {
      "use strict";
      if (!utils.isArray(array)) {
          this.log("eachThen() only works with arrays", "error");
          return this;
      }
      array.forEach(function _forEach(item) {
          this.then(function() {
              this.then(this.createStep(then, {data: item}));
          });
      }, this);
      return this;
  };
  
  /**
   * Prints something to stdout.
   *
   * @param  String  text   A string to echo to stdout
   * @param  String  style  An optional style name
   * @param  Number  pad    An optional pad value
   * @return Casper
   */
  Casper.prototype.echo = function echo(text, style, pad) {
      "use strict";
      if (!utils.isString(text)) {
          try {
              text = text.toString();
          } catch (e) {
              try {
                  text = utils.serialize(text);
              } catch (e2) {
                  text = '';
              }
          }
      }
      var message = style ? this.colorizer.colorize(text, style, pad) : text;
      console.log(this.filter('echo.message', message) || message);
      return this;
  };
  
  /**
   * Evaluates an expression in the page context, a bit like what
   * WebPage#evaluate does, but the passed function can also accept
   * parameters if a context Object is also passed:
   *
   *     casper.evaluate(function(username, password) {
   *         document.querySelector('#username').value = username;
   *         document.querySelector('#password').value = password;
   *         document.querySelector('#submit').click();
   *     }, 'Bazoonga', 'baz00nga');
   *
   * @param  Function  fn       The function to be evaluated within current page DOM
   * @param  Object    context  Object containing the parameters to inject into the function
   * @return mixed
   * @see    WebPage#evaluate
   */
  Casper.prototype.evaluate = function evaluate(fn, context) {
      "use strict";
      this.checkStarted();
      // check whether javascript is enabled !!
      if (this.options.pageSettings.javascriptEnabled === false) {
          throw new CasperError("evaluate() requires javascript to be enabled");
      }
      // preliminary checks
      if (!utils.isFunction(fn) && !utils.isString(fn)) { // phantomjs allows functions defs as string
          throw new CasperError("evaluate() only accepts functions or strings");
      }
      // ensure client utils are always injected
      this.injectClientUtils();
      // function context
      if (arguments.length === 1) {
          return utils.clone(this.page.evaluate(fn));
      } else if (arguments.length === 2) {
          // check for closure signature if it matches context
          if (utils.isObject(context) && eval(fn).length === Object.keys(context).length) {
              context = utils.objectValues(context);
          } else {
              context = [context];
          }
      } else {
          // phantomjs-style signature
          context = [].slice.call(arguments, 1);
      }
      return utils.clone(this.page.evaluate.apply(this.page, [fn].concat(context)));
  };
  
  /**
   * Evaluates an expression within the current page DOM and die() if it
   * returns false.
   *
   * @param  function  fn       The expression to evaluate
   * @param  String    message  The error message to log
   * @param  Number  status   An optional exit status code (must be > 0)
   *
   * @return Casper
   */
  Casper.prototype.evaluateOrDie = function evaluateOrDie(fn, message, status) {
      "use strict";
      this.checkStarted();
      if (!this.evaluate(fn)) {
          return this.die(message, status);
      }
      return this;
  };
  
  /**
   * Checks if an element matching the provided DOM CSS3/XPath selector exists in
   * current page DOM.
   *
   * @param  String  selector  A DOM CSS3/XPath selector
   * @return Boolean
   */
  Casper.prototype.exists = function exists(selector) {
      "use strict";
      this.checkStarted();
      return this.callUtils("exists", selector);
  };
  
  /**
   * Exits phantom.
   *
   * @param  Number  status  Status
   * @return Casper
   */
  Casper.prototype.exit = function exit(status) {
      "use strict";
      this.emit('exit', status);
      phantom.exit(status);
  };
  
  /**
   * Fetches plain text contents contained in the DOM element(s) matching a given CSS3/XPath
   * selector.
   *
   * @param  String  selector  A DOM CSS3/XPath selector
   * @return String
   */
  Casper.prototype.fetchText = function fetchText(selector) {
      "use strict";
      this.checkStarted();
      return this.callUtils("fetchText", selector);
  };
  
  /**
   * Fills a form with provided field values.
   *
   * @param  String selector  A DOM CSS3/XPath selector to the target form to fill
   * @param  Object vals      Field values
   * @param  Object options   The fill settings (optional)
   */
  Casper.prototype.fillForm = function fillForm(selector, vals, options) {
      "use strict";
      this.checkStarted();
  
      var selectorType = options && options.selectorType || "names",
          submit = !!(options && options.submit);
  
      this.emit('fill', selector, vals, options);
  
      var fillResults = this.evaluate(function _evaluate(selector, vals, selectorType) {
          try {
              return __utils__.fill(selector, vals, selectorType);
          } catch (exception) {
              return {exception: exception.toString()};
          }
      }, selector, vals, selectorType);
  
      if (!fillResults) {
          throw new CasperError("Unable to fill form");
      } else if (fillResults && fillResults.exception) {
          throw new CasperError("Unable to fill form: " + fillResults.exception);
      } else if (fillResults.errors.length > 0) {
          throw new CasperError(f('Errors encountered while filling form: %s',
                                fillResults.errors.join('; ')));
      }
  
      // File uploads
      if (fillResults.files && fillResults.files.length > 0) {
          if (utils.isObject(selector) && selector.type === 'xpath') {
              this.warn('Filling file upload fields is currently not supported using ' +
                        'XPath selectors; Please use a CSS selector instead.');
          } else {
              fillResults.files.forEach(function _forEach(file) {
                  if (!file || !file.path) {
                      return;
                  }
                  if (!fs.exists(file.path)) {
                      throw new CasperError('Cannot upload nonexistent file: ' + file.path);
                  }
                  var fileFieldSelector;
                  if (file.type === "names") {
                      fileFieldSelector = [selector, 'input[name="' + file.selector + '"]'].join(' ');
                  } else if (file.type === "css" || file.type === "labels") {
                      fileFieldSelector = [selector, file.selector].join(' ');
                  }
                  this.page.uploadFile(fileFieldSelector, file.path);
              }.bind(this));
          }
      }
      // Form submission?
      if (submit) {
          this.evaluate(function _evaluate(selector) {
              var form = __utils__.findOne(selector);
              var method = (form.getAttribute('method') || "GET").toUpperCase();
              var action = form.getAttribute('action') || "unknown";
              __utils__.log('submitting form to ' + action + ', HTTP ' + method, 'info');
              var event = document.createEvent('Event');
              event.initEvent('submit', true, true);
              if (!form.dispatchEvent(event)) {
                  __utils__.log('unable to submit form', 'warning');
                  return;
              }
              if (typeof form.submit === "function") {
                  form.submit();
              } else {
                  // http://www.spiration.co.uk/post/1232/Submit-is-not-a-function
                  form.submit.click();
              }
          }, selector);
      }
  }
  
  /**
   * Fills a form with provided field values using the Name attribute.
   *
   * @param  String  formSelector  A DOM CSS3/XPath selector to the target form to fill
   * @param  Object  vals          Field values
   * @param  Boolean submit        Submit the form?
   */
  Casper.prototype.fillNames = function fillNames(formSelector, vals, submit) {
      "use strict";
      return this.fillForm(formSelector, vals, {
          submit: submit,
          selectorType: 'names'
      });
  };
  
  /**
   * Fills a form with provided field values using associated label text.
   *
   * @param  String  formSelector  A DOM CSS3/XPath selector to the target form to fill
   * @param  Object  vals          Field values
   * @param  Boolean submit        Submit the form?
   */
  Casper.prototype.fillLabels = function fillLabels(formSelector, vals, submit) {
      "use strict";
      return this.fillForm(formSelector, vals, {
          submit: submit,
          selectorType: 'labels'
      });
  };
  
  /**
   * Fills a form with provided field values using CSS3 selectors.
   *
   * @param  String  formSelector  A DOM CSS3/XPath selector to the target form to fill
   * @param  Object  vals          Field values
   * @param  Boolean submit        Submit the form?
   */
  Casper.prototype.fillSelectors = function fillSelectors(formSelector, vals, submit) {
      "use strict";
      return this.fillForm(formSelector, vals, {
          submit: submit,
          selectorType: 'css'
      });
  };
  
  /**
   * Fills a form with provided field values using the Name attribute by default.
   *
   * @param  String  formSelector  A DOM CSS3/XPath selector to the target form to fill
   * @param  Object  vals          Field values
   * @param  Boolean submit        Submit the form?
   */
  Casper.prototype.fill = Casper.prototype.fillNames;
  
  /**
   * Fills a form with provided field values using XPath selectors.
   *
   * @param  String  formSelector  A DOM CSS3/XPath selector to the target form to fill
   * @param  Object  vals          Field values
   * @param  Boolean submit        Submit the form?
   */
  Casper.prototype.fillXPath = function fillXPath(formSelector, vals, submit) {
      "use strict";
      return this.fillForm(formSelector, vals, {
          submit: submit,
          selectorType: 'xpath'
      });
  };
  
  /**
   * Go a step forward in browser's history
   *
   * @return Casper
   */
  Casper.prototype.forward = function forward() {
      "use strict";
      this.checkStarted();
      return this.then(function() {
          this.emit('forward');
          this.page.goForward();
      });
  };
  
  /**
   * Creates a new Colorizer instance. Sets `Casper.options.type` to change the
   * colorizer type name (see the `colorizer` module).
   *
   * @return Object
   */
  Casper.prototype.getColorizer = function getColorizer() {
      "use strict";
      return colorizer.create(this.options.colorizerType || 'Colorizer');
  };
  
  /**
   * Retrieves current page contents, dealing with exotic other content types than HTML.
   *
   * @return String
   */
  Casper.prototype.getPageContent = function getPageContent() {
      "use strict";
      this.checkStarted();
      var contentType = utils.getPropertyPath(this, 'currentResponse.contentType');
      if (!utils.isString(contentType) || contentType.indexOf("text/html") !== -1) {
          return this.page.frameContent;
      }
      return this.page.framePlainText;
  };
  
  /**
   * Retrieves current document url.
   *
   * @return String
   */
  Casper.prototype.getCurrentUrl = function getCurrentUrl() {
      "use strict";
      this.checkStarted();
      try {
          if (this.options.pageSettings.javascriptEnabled === false) {
              return this.page.url;
          } else {
              return utils.decodeUrl(this.evaluate(function _evaluate() {
                  return document.location.href;
              }));
          }
      } catch (e) {
          // most likely the current page object has been "deleted" (think closed popup)
          if (/deleted QObject/.test(e.message))
              return "";
          throw e;
      }
  };
  
  /**
   * Retrieves the value of an attribute on the first element matching the provided
   * DOM CSS3/XPath selector.
   *
   * @param  String  selector   A DOM CSS3/XPath selector
   * @param  String  attribute  The attribute name to lookup
   * @return String  The requested DOM element attribute value
   */
  Casper.prototype.getElementAttribute =
  Casper.prototype.getElementAttr = function getElementAttr(selector, attribute) {
      "use strict";
      this.checkStarted();
      return this.evaluate(function _evaluate(selector, attribute) {
          return __utils__.findOne(selector).getAttribute(attribute);
      }, selector, attribute);
  };
  
  /**
   * Retrieves the value of an attribute for each element matching the provided
   * DOM CSS3/XPath selector.
   *
   * @param  String  selector   A DOM CSS3/XPath selector
   * @param  String  attribute  The attribute name to lookup
   * @return Array
   */
  Casper.prototype.getElementsAttribute =
  Casper.prototype.getElementsAttr = function getElementsAttr(selector, attribute) {
      "use strict";
      this.checkStarted();
      return this.evaluate(function _evaluate(selector, attribute) {
          return [].map.call(__utils__.findAll(selector), function(element) {
              return element.getAttribute(attribute);
          });
      }, selector, attribute);
  }
  
  /**
   * Retrieves boundaries for a DOM element matching the provided DOM CSS3/XPath selector.
   *
   * @param  String  selector  A DOM CSS3/XPath selector
   * @return Object
   */
  Casper.prototype.getElementBounds = function getElementBounds(selector) {
      "use strict";
      this.checkStarted();
      if (!this.exists(selector)) {
          throw new CasperError("No element matching selector found: " + selector);
      }
      var zoomFactor = this.page.zoomFactor || 1;
      var clipRect = this.callUtils("getElementBounds", selector);
      if (zoomFactor !== 1) {
          for (var prop in clipRect) {
              if (clipRect.hasOwnProperty(prop)) {
                  clipRect[prop] = clipRect[prop] * zoomFactor;
              }
          }
      }
      if (!utils.isClipRect(clipRect)) {
          throw new CasperError('Could not fetch boundaries for element matching selector: ' + selector);
      }
      return clipRect;
  };
  
  /**
   * Retrieves information about the node matching the provided selector.
   *
   * @param  String|Objects  selector  CSS3/XPath selector
   * @return Object
   */
  Casper.prototype.getElementInfo = function getElementInfo(selector) {
      "use strict";
      this.checkStarted();
      if (!this.exists(selector)) {
          throw new CasperError(f("Cannot get informations from %s: element not found.", selector));
      }
      return this.callUtils("getElementInfo", selector);
  };
  
  /**
   * Retrieves information about the nodes matching the provided selector.
   *
   * @param String|Objects  selector  CSS3/XPath selector
   * @return Array
   */
  Casper.prototype.getElementsInfo = function getElementsInfo(selector) {
      "use strict";
      this.checkStarted();
      if (!this.exists(selector)) {
          throw new CasperError(f("Cannot get information from %s: no elements found.", selector));
      }
      return this.callUtils("getElementsInfo", selector);
  };
  
  /**
   * Retrieves boundaries for all the DOM elements matching the provided DOM CSS3/XPath selector.
   *
   * @param  String  selector  A DOM CSS3/XPath selector
   * @return Array
   */
  Casper.prototype.getElementsBounds = function getElementsBounds(selector) {
      "use strict";
      this.checkStarted();
      if (!this.exists(selector)) {
          throw new CasperError("No element matching selector found: " + selector);
      }
      var zoomFactor = this.page.zoomFactor || 1;
      var clipRects = this.callUtils("getElementsBounds", selector);
      if (zoomFactor !== 1) {
          Array.prototype.forEach.call(clipRects, function(clipRect) {
              for (var prop in clipRect) {
                  if (clipRect.hasOwnProperty(prop)) {
                      clipRect[prop] = clipRect[prop] * zoomFactor;
                  }
              }
          });
      }
      return clipRects;
  };
  
  /**
   * Retrieves a given form all of its field values.
   *
   * @param  String  selector  A DOM CSS3/XPath selector
   * @return Object
   */
  Casper.prototype.getFormValues = function(selector) {
      "use strict";
      this.checkStarted();
      if (!this.exists(selector)) {
          throw new CasperError(f('Form matching selector "%s" not found', selector));
      }
      return this.callUtils("getFormValues", selector);
  };
  
  /**
   * Retrieves global variable.
   *
   * @param  String  name  The name of the global variable to retrieve
   * @return mixed
   */
  Casper.prototype.getGlobal = function getGlobal(name) {
      "use strict";
      this.checkStarted();
      var result = this.evaluate(function _evaluate(name) {
          var result = {};
          try {
              result.value = JSON.stringify(window[name]);
          } catch (e) {
              var message = "Unable to JSON encode window." + name + ": " + e;
              __utils__.log(message, "error");
              result.error = message;
          }
          return result;
      }, name);
      if (!utils.isObject(result)) {
          throw new CasperError(f('Could not retrieve global value for "%s"', name));
      } else if ('error' in result) {
          throw new CasperError(result.error);
      } else if (utils.isString(result.value)) {
          return JSON.parse(result.value);
      }
  };
  
  /**
   * Retrieves current HTML code matching the provided CSS3/XPath selector.
   * Returns the HTML contents for the whole page if no arg is passed.
   *
   * @param  String   selector  A DOM CSS3/XPath selector
   * @param  Boolean  outer     Whether to fetch outer HTML contents (default: false)
   * @return String
   */
  Casper.prototype.getHTML = function getHTML(selector, outer) {
      "use strict";
      this.checkStarted();
      if (!selector) {
          return this.page.frameContent;
      }
      if (!this.exists(selector)) {
          throw new CasperError("No element matching selector found: " + selector);
      }
      return this.evaluate(function getSelectorHTML(selector, outer) {
          var element = __utils__.findOne(selector);
          return outer ? element.outerHTML : element.innerHTML;
      }, selector, !!outer);
  };
  
  /**
   * Retrieves current page title, if any.
   *
   * @return String
   */
  Casper.prototype.getTitle = function getTitle() {
      "use strict";
      this.checkStarted();
      return this.evaluate(function _evaluate() {
          return document.title;
      });
  };
  
  /**
   * Handles received HTTP resource.
   *
   * @param  Object  resource  PhantomJS HTTP resource
   */
  Casper.prototype.handleReceivedResource = function(resource) {
      "use strict";
      /*jshint maxstatements:20*/
      if (resource.stage !== "end") {
          return;
      }
      this.resources.push(resource);
      if (utils.decodeUrl(resource.url) !== this.requestUrl) {
          return;
      }
      this.currentHTTPStatus = null;
      this.currentResponse = {};
      if (utils.isHTTPResource(resource)) {
          this.emit('page.resource.received', resource);
          this.currentResponse = resource;
          this.currentHTTPStatus = resource.status;
          this.emit('http.status.' + resource.status, resource);
          if (utils.isObject(this.options.httpStatusHandlers) &&
              resource.status in this.options.httpStatusHandlers &&
              utils.isFunction(this.options.httpStatusHandlers[resource.status])) {
              this.options.httpStatusHandlers[resource.status].call(this, this, resource);
          }
      }
      this.currentUrl = resource.url;
      this.emit('location.changed', resource.url);
  };
  
  /**
   * Initializes PhantomJS error handler.
   *
   */
  Casper.prototype.initErrorHandler = function initErrorHandler() {
      "use strict";
      var casper = this;
      phantom.onError = function phantom_onError(msg, backtrace) {
          casper.emit('error', msg, backtrace);
          if (casper.options.exitOnError === true) {
              casper.exit(1);
          }
      };
  };
  
  /**
   * Injects configured local client scripts.
   *
   * @return Casper
   */
  Casper.prototype.injectClientScripts = function injectClientScripts() {
      "use strict";
      this.checkStarted();
      if (!this.options.clientScripts) {
          return;
      }
      if (utils.isString(this.options.clientScripts)) {
          this.options.clientScripts = [this.options.clientScripts];
      }
      if (!utils.isArray(this.options.clientScripts)) {
          throw new CasperError("The clientScripts option must be an array");
      }
      this.options.clientScripts.forEach(function _forEach(script) {
          if (this.page.injectJs(script)) {
              this.log(f('Automatically injected %s client side', script), "debug");
          } else {
              this.warn('Failed injecting %s client side', script);
          }
      }.bind(this));
      return this;
  };
  
  /**
   * Injects Client-side utilities in current page context.
   *
   */
  Casper.prototype.injectClientUtils = function injectClientUtils() {
      "use strict";
      this.checkStarted();
      var clientUtilsInjected = this.page.evaluate(function() {
          return typeof __utils__ === "object";
      });
      if (true === clientUtilsInjected) {
          return;
      }
      var clientUtilsPath = require('fs').pathJoin(phantom.casperPath, 'modules', 'clientutils.js');
      if (true === this.page.injectJs(clientUtilsPath)) {
          this.log("Successfully injected Casper client-side utilities", "debug");
      } else {
          this.warn("Failed to inject Casper client-side utilities");
      }
      // ClientUtils and Casper shares the same options
      // These are not the lines I'm the most proud of in my life, but it works.
      /*global __options*/
      this.page.evaluate(function() {
          window.__utils__ = new window.ClientUtils(__options);
      }.toString().replace('__options', JSON.stringify(this.options)));
  };
  
  /**
   * Loads and include remote client scripts to current page.
   *
   * @return Casper
   */
  Casper.prototype.includeRemoteScripts = function includeRemoteScripts() {
      "use strict";
      var numScripts = this.options.remoteScripts.length, loaded = 0;
      if (numScripts === 0) {
          return this;
      }
      this.waitStart();
      this.options.remoteScripts.forEach(function(scriptUrl) {
          this.log(f("Loading remote script: %s", scriptUrl), "debug");
          this.page.includeJs(scriptUrl, function() {
              loaded++;
              this.log(f("Remote script %s loaded", scriptUrl), "debug");
              if (loaded === numScripts) {
                  this.log("All remote scripts loaded.", "debug");
                  this.waitDone();
              }
          }.bind(this));
      }.bind(this));
      return this;
  };
  
  /**
   * Logs a message.
   *
   * @param  String  message  The message to log
   * @param  String  level    The log message level (from Casper.logLevels property)
   * @param  String  space    Space from where the logged event occurred (default: "phantom")
   * @return Casper
   */
  Casper.prototype.log = function log(message, level, space) {
      "use strict";
      level = level && this.logLevels.indexOf(level) > -1 ? level : "debug";
      space = space ? space : "phantom";
      if (level === "error" && utils.isFunction(this.options.onError)) {
          this.options.onError.call(this, this, message, space);
      }
      if (this.logLevels.indexOf(level) < this.logLevels.indexOf(this.options.logLevel)) {
          return this; // skip logging
      }
      var entry = {
          level:   level,
          space:   space,
          message: message,
          date:    new Date().toString()
      };
      if (level in this.logFormats && utils.isFunction(this.logFormats[level])) {
          message = this.logFormats[level](message, level, space);
      } else {
          message = f('%s [%s] %s',
                      this.colorizer.colorize(f('[%s]', level), this.logStyles[level]),
                      space,
                      message);
      }
      if (this.options.verbose) {
          this.echo(this.filter('log.message', message) || message); // direct output
      }
      this.result.log.push(entry);
      this.emit('log', entry);
      return this;
  };
  
  /**
   * Emulates an event on the element from the provided selector using the mouse
   * pointer, if possible.
   *
   * In case of success, `true` is returned, `false` otherwise.
   *
   * @param  String   type      Type of event to emulate
   * @param  String   selector  A DOM CSS3 compatible selector
   * @return Boolean
   */
  Casper.prototype.mouseEvent = function mouseEvent(type, selector) {
      "use strict";
      this.checkStarted();
      this.log("Mouse event '" + type + "' on selector: " + selector, "debug");
      if (!this.exists(selector)) {
          throw new CasperError(f("Cannot dispatch %s event on nonexistent selector: %s", type, selector));
      }
      if (this.callUtils("mouseEvent", type, selector)) {
          return true;
      }
      // fallback onto native QtWebKit mouse events
      try {
          return this.mouse.processEvent(type, selector);
      } catch (e) {
          this.log(f("Couldn't emulate '%s' event on %s: %s", type, selector, e), "error");
      }
      return false;
  };
  
  /**
   * Performs an HTTP request, with optional settings.
   *
   * Available settings are:
   *
   * - String  method:   The HTTP method to use
   * - Object  data:     The data to use to perform the request, eg. {foo: 'bar'}
   * - Object  headers:  Custom request headers object, eg. {'Cache-Control': 'max-age=0'}
   *
   * @param  String  location  The url to open
   * @param  Object  settings  The request settings (optional)
   * @return Casper
   */
  Casper.prototype.open = function open(location, settings) {
      "use strict";
      /*jshint maxstatements:30*/
      var baseCustomHeaders = this.page.customHeaders,
          customHeaders = settings && settings.headers || {};
      this.checkStarted();
      settings = utils.isObject(settings) ? settings : {};
      settings.method = settings.method || "get";
      // http method
      // taken from https://github.com/ariya/phantomjs/blob/master/src/webpage.cpp#L302
      var methods = ["get", "head", "put", "post", "delete"];
      if (settings.method && (!utils.isString(settings.method) || methods.indexOf(settings.method.toLowerCase()) === -1)) {
          throw new CasperError("open(): settings.method must be part of " + methods.join(', '));
      }
      // http data
      if (settings.data) {
          if (utils.isObject(settings.data)) { // query object
              if (settings.headers && settings.headers["Content-Type"].match(/application\/json/)) {
                  settings.data = JSON.stringify(settings.data); // convert object to JSON notation
              } else {
                  settings.data = qs.encode(settings.data); // escapes all characters except alphabetic, decimal digits and ,-_.!~*'()
              }
          } else if (!utils.isString(settings.data)) {
              throw new CasperError("open(): invalid request settings data value: " + settings.data);
          }
      }
      // clean location
      location = utils.cleanUrl(location);
      // current request url
      this.configureHttpAuth(location, settings);
      this.requestUrl = this.filter('open.location', location) || location;
      this.emit('open', this.requestUrl, settings);
      this.log(f('opening url: %s, HTTP %s', this.requestUrl, settings.method.toUpperCase()), "debug");
      // reset resources
      this.resources = [];
      // custom headers
      this.page.customHeaders = utils.mergeObjects(utils.clone(baseCustomHeaders), customHeaders);
      // perfom request
      this.browserInitializing = true;
      this.page.openUrl(this.requestUrl, {
          operation: settings.method,
          data:      settings.data
      }, this.page.settings);
      // revert base custom headers
      this.page.customHeaders = baseCustomHeaders;
      return this;
  };
  
  /**
   * Reloads current page.
   *
   * @param  Function  then  a next step function
   * @return Casper
   */
  Casper.prototype.reload = function reload(then) {
      "use strict";
      this.checkStarted();
      this.then(function() {
          this.page.reload();
      });
      if (utils.isFunction(then)) {
          this.then(this.createStep(then));
      }
      return this;
  };
  
  /**
   * Repeats a step a given number of times.
   *
   * @param  Number    times  Number of times to repeat step
   * @aram   function  then   The step closure
   * @return Casper
   * @see    Casper#then
   */
  Casper.prototype.repeat = function repeat(times, then) {
      "use strict";
      for (var i = 0; i < times; i++) {
          this.then(then);
      }
      return this;
  };
  
  /**
   * Checks if a given resource was loaded by the remote page.
   *
   * @param  Function/String/RegExp  test  A test function, string or regular expression.
   *                                       In case a string is passed, url matching will be tested.
   * @return Boolean
   */
  Casper.prototype.resourceExists = function resourceExists(test) {
      "use strict";
      this.checkStarted();
      var testFn;
      switch (utils.betterTypeOf(test)) {
          case "string":
              testFn = function _testResourceExists_String(res) {
                  return res.url.indexOf(test) !== -1 && res.status !== 404;
              };
              break;
          case "regexp":
              testFn = function _testResourceExists_Regexp(res) {
                  return test.test(res.url) && res.status !== 404;
              };
              break;
          case "function":
              testFn = test;
              if (phantom.casperEngine !== "slimerjs")
                  testFn.name = "_testResourceExists_Function";
              break;
          default:
              throw new CasperError("Invalid type");
      }
      return this.resources.some(testFn);
  };
  
  /**
   * Runs the whole suite of steps.
   *
   * @param  function  onComplete  an optional callback
   * @param  Number    time        an optional amount of milliseconds for interval checking
   * @return Casper
   */
  Casper.prototype.run = function run(onComplete, time) {
      "use strict";
      this.checkStarted();
      if (!this.steps || this.steps.length < 1) {
          throw new CasperError('No steps defined, aborting');
      }
      this.log(f("Running suite: %d step%s", this.steps.length, this.steps.length > 1 ? "s" : ""), "info");
      this.emit('run.start');
      this.checker = setInterval(this.checkStep, (time ? time: this.options.retryTimeout), this, onComplete);
      return this;
  };
  
  /**
   * Runs a step.
   *
   * @param  Function  step
   */
  Casper.prototype.runStep = function runStep(step) {
      "use strict";
      /*jshint maxstatements:20*/
      this.checkStarted();
      var skipLog = utils.isObject(step.options) && step.options.skipLog === true,
          stepInfo = f("Step %s %d/%d", step.name || "anonymous", this.step, this.steps.length),
          stepResult;
      function getCurrentSuiteId(casper) {
          try {
              return casper.test.getCurrentSuiteId();
          } catch (e) {
              return casper.step;
          }
      }
      if (!skipLog && /^http/.test(this.getCurrentUrl())) {
          this.log(stepInfo + f(' %s (HTTP %d)', this.getCurrentUrl(), this.currentHTTPStatus), "info");
      }
      if (utils.isNumber(this.options.stepTimeout) && this.options.stepTimeout > 0) {
          var stepTimeoutCheckInterval = setInterval(function _check(self, start, stepNum) {
              if (new Date().getTime() - start > self.options.stepTimeout) {
                  if (getCurrentSuiteId(self) === stepNum) {
                      self.emit('step.timeout', stepNum, self.options.onStepTimeout);
                      if (utils.isFunction(self.options.onStepTimeout)) {
                          self.options.onStepTimeout.call(self, self.options.stepTimeout, stepNum);
                      }
                  }
                  clearInterval(stepTimeoutCheckInterval);
              }
          }, this.options.stepTimeout, this, new Date().getTime(), getCurrentSuiteId(this));
      }
      this.emit('step.start', step);
      if (this.currentResponse) {
          this.currentResponse.data = step.options && step.options.data || null;
      }
      try {
          stepResult = step.call(this, this.currentResponse);
          if (utils.isFunction(this.options.onStepComplete)) {
              this.options.onStepComplete.call(this, this, stepResult);
          }
      } catch (err) {
          this.emit('step.error', err);
          if (!this.options.silentErrors) {
              throw err;
          }
      }
      if (!skipLog) {
          this.emit('step.complete', stepResult);
          this.log(stepInfo + f(": done in %dms.", new Date().getTime() - this.startTime), "info");
      }
  };
  
  /**
   * Sends keys to given element.
   *
   * Options:
   *
   * - eventType: "keypress", "keyup" or "keydown" (default: "keypress")
   * - modifiers: a string defining the key modifiers, eg. "alt", "alt+shift"
   *
   * @param  String  selector  A DOM CSS3 compatible selector
   * @param  String  keys      A string representing the sequence of char codes to send
   * @param  Object  options   Options
   * @return Casper
   */
  Casper.prototype.sendKeys = function(selector, keys, options) {
      "use strict";
      this.checkStarted();
      options = utils.mergeObjects({
          eventType: 'keypress',
          reset: false
      }, options || {});
      var elemInfos = this.getElementInfo(selector),
          tag = elemInfos.nodeName.toLowerCase(),
          type = utils.getPropertyPath(elemInfos, 'attributes.type'),
          supported = ["color", "date", "datetime", "datetime-local", "email",
                       "hidden", "month", "number", "password", "range", "search",
                       "tel", "text", "time", "url", "week"],
          isTextInput = false,
          isTextArea = tag === 'textarea',
          isValidInput = tag === 'input' && (typeof type === 'undefined' || supported.indexOf(type) !== -1),
          isContentEditable = !!elemInfos.attributes.contenteditable;
  
      if (isTextArea || isValidInput || isContentEditable) {
          // clicking on the input element brings it focus
          isTextInput = true;
          this.click(selector);
      }
      if (options.reset) {
          this.evaluate(function(selector) {
              __utils__.setField(__utils__.findOne(selector), '');
          }, selector);
          this.click(selector);
      }
      var modifiers = utils.computeModifier(options && options.modifiers,
                                            this.page.event.modifier)
      this.page.sendEvent(options.eventType, keys, null, null, modifiers);
      if (isTextInput && !options.keepFocus) {
          // remove the focus
          this.evaluate(function(selector) {
              __utils__.findOne(selector).blur();
          }, selector);
      }
      return this;
  };
  
  /**
   * Scrolls current document to x, y coordinates.
   *
   * @param  {Number} x X position
   * @param  {Number} y Y position
   * @return {Casper}
   */
  Casper.prototype.scrollTo = function(x, y) {
      "use strict";
      this.callUtils("scrollTo", x, y);
      return this;
  };
  
  /**
   * Scrolls current document up to its bottom.
   *
   * @return {Casper}
   */
  Casper.prototype.scrollToBottom = function scrollToBottom() {
      "use strict";
      this.callUtils("scrollToBottom");
      return this;
  };
  
  /**
   * Sets current page content.
   *
   * @param  String  content  Desired page content
   * @return Casper
   */
  Casper.prototype.setContent = function setContent(content) {
      "use strict";
      this.checkStarted();
      this.page.content = content;
      return this;
  };
  
  /**
   * Sets current WebPage instance the credentials for HTTP authentication.
   *
   * @param  String  username
   * @param  String  password
   * @return Casper
   */
  Casper.prototype.setHttpAuth = function setHttpAuth(username, password) {
      "use strict";
      this.checkStarted();
      this.page.settings.userName = username;
      this.page.settings.password = password;
      return this;
  };
  
  /**
   * Configures and starts Casper.
   *
   * @param  String   location  An optional location to open on start
   * @param  function then      Next step function to execute on page loaded (optional)
   * @return Casper
   */
  Casper.prototype.start = function start(location, then) {
      "use strict";
      /*jshint maxstatements:30*/
      this.emit('starting');
      this.log('Starting...', "info");
      this.startTime = new Date().getTime();
      this.currentResponse = {};
      this.history = [];
      this.popups = pagestack.create();
      this.steps = [];
      this.step = 0;
      // Option checks
      if (this.logLevels.indexOf(this.options.logLevel) < 0) {
          this.log(f("Unknown log level '%d', defaulting to 'warning'", this.options.logLevel), "warning");
          this.options.logLevel = "warning";
      }
      if (!utils.isWebPage(this.page)) {
          this.page = this.mainPage = utils.isWebPage(this.options.page) ? this.options.page : createPage(this);
      }
      this.page.settings = utils.mergeObjects(this.page.settings, this.options.pageSettings);
      if (utils.isClipRect(this.options.clipRect)) {
          this.page.clipRect = this.options.clipRect;
      }
      if (utils.isObject(this.options.viewportSize)) {
          this.page.viewportSize = this.options.viewportSize;
      }
      // timeout handling
      if (utils.isNumber(this.options.timeout) && this.options.timeout > 0) {
          this.log(f("Execution timeout set to %dms", this.options.timeout), "info");
          setTimeout(function _check(self) {
              self.emit('timeout');
              if (utils.isFunction(self.options.onTimeout)) {
                  self.options.onTimeout.call(self, self.options.timeout);
              }
          }, this.options.timeout, this);
      }
      this.started = true;
      this.emit('started');
      if (utils.isString(location) && location.length > 0) {
          return this.thenOpen(location, utils.isFunction(then) ? then : this.createStep(function _step() {
              this.log("start page is loaded", "debug");
          }, {skipLog: true}));
      }
      return this;
  };
  
  /**
   * Returns the current status of current instance
   *
   * @param  Boolean  asString  Export status object as string
   * @return Object
   */
  Casper.prototype.status = function status(asString) {
      "use strict";
      var properties = ['currentHTTPStatus', 'loadInProgress', 'navigationRequested',
                        'options', 'pendingWait', 'requestUrl', 'started', 'step', 'url'];
      var currentStatus = {};
      properties.forEach(function(property) {
          currentStatus[property] = this[property];
      }.bind(this));
      return asString === true ? utils.dump(currentStatus) : currentStatus;
  };
  
  /**
   * Schedules the next step in the navigation process.
   *
   * @param  function  step  A function to be called as a step
   * @return Casper
   */
  Casper.prototype.then = function then(step) {
      "use strict";
      this.checkStarted();
      if (!utils.isFunction(step)) {
          throw new CasperError("You can only define a step as a function");
      }
      // check if casper is running
      if (this.checker === null) {
          // append step to the end of the queue
          step.level = 0;
          this.steps.push(step);
      } else {
          // insert substep a level deeper
          try {
              step.level = this.steps[this.step - 1].level + 1;
          } catch (e) {
              step.level = 0;
          }
          var insertIndex = this.step;
          while (this.steps[insertIndex] && step.level === this.steps[insertIndex].level) {
              insertIndex++;
          }
          this.steps.splice(insertIndex, 0, step);
      }
      this.emit('step.added', step);
      return this;
  };
  
  /**
   * Adds a new navigation step for clicking on a provided link selector
   * and execute an optional next step.
   *
   * @param  String   selector        A DOM CSS3 compatible selector
   * @param  Function then            Next step function to execute on page loaded (optional)
   * @return Casper
   * @see    Casper#click
   * @see    Casper#then
   */
  Casper.prototype.thenClick = function thenClick(selector, then) {
      "use strict";
      this.checkStarted();
      this.then(function _step() {
          this.click(selector);
      });
      return utils.isFunction(then) ? this.then(then) : this;
  };
  
  /**
   * Adds a new navigation step to perform code evaluation within the
   * current retrieved page DOM.
   *
   * @param  function  fn       The function to be evaluated within current page DOM
   * @param  object    context  Optional function parameters context
   * @return Casper
   * @see    Casper#evaluate
   */
  Casper.prototype.thenEvaluate = function thenEvaluate(fn, context) {
      "use strict";
      this.checkStarted();
      var args = [fn].concat([].slice.call(arguments, 1));
      return this.then(function _step() {
          this.evaluate.apply(this, args);
      });
  };
  
  /**
   * Adds a new navigation step for opening the provided location.
   *
   * @param  String   location  The URL to load
   * @param  function then      Next step function to execute on page loaded (optional)
   * @return Casper
   * @see    Casper#open
   */
  Casper.prototype.thenOpen = function thenOpen(location, settings, then) {
      "use strict";
      this.checkStarted();
      if (!(settings && !utils.isFunction(settings))) {
        then = settings;
        settings = null;
      }
      this.then(this.createStep(function _step() {
          this.open(location, settings);
      }, {
          skipLog: true
      }));
      return utils.isFunction(then) ? this.then(then) : this;
  };
  
  /**
   * Adds a step which bypasses `nb` steps.
   *
   * @param  Integer  nb  Number of steps to bypass
   */
  Casper.prototype.thenBypass = function thenBypass(nb) {
      "use strict";
      return this.then(function _thenBypass() {
          this.bypass(nb);
      });
  };
  
  /**
   * Bypass `nb` steps if condition is true.
   *
   * @param  Mixed    condition  Test condition
   * @param  Integer  nb         Number of steps to bypass
   */
  Casper.prototype.thenBypassIf = function thenBypassIf(condition, nb) {
      "use strict";
      return this.then(function _thenBypassIf() {
          if (utils.isFunction(condition)) {
              condition = condition.call(this);
          }
          if (utils.isTruthy(condition)) {
              this.bypass(nb);
          }
      });
  };
  
  /**
   * Bypass `nb` steps if condition is false.
   *
   * @param Mixed    condition  Test condition
   * @param Integer  nb         Number of tests to bypass
   */
  Casper.prototype.thenBypassUnless = function thenBypassUnless(condition, nb) {
      "use strict";
      return this.then(function _thenBypassUnless() {
          if (utils.isFunction(condition)) {
              condition = condition.call(this);
          }
          if (utils.isFalsy(condition)) {
              this.bypass(nb);
          }
      });
  };
  
  /**
   * Adds a new navigation step for opening and evaluate an expression
   * against the DOM retrieved from the provided location.
   *
   * @param  String    location  The url to open
   * @param  function  fn        The function to be evaluated within current page DOM
   * @param  object    context   Optional function parameters context
   * @return Casper
   * @see    Casper#evaluate
   * @see    Casper#open
   */
  Casper.prototype.thenOpenAndEvaluate = function thenOpenAndEvaluate(location, fn, context) {
      "use strict";
      this.checkStarted();
      return this.thenOpen(location).thenEvaluate(fn, context);
  };
  
  /**
   * Returns a string representation of current instance
   *
   * @return String
   */
  Casper.prototype.toString = function toString() {
      "use strict";
      return '[object Casper], currently at ' + this.getCurrentUrl();
  };
  
  /**
   * Clear all wait processes.
   *
   * @return Casper
   */
  Casper.prototype.unwait = function unwait() {
      "use strict";
      this.waiters.forEach(function(interval) {
          if (interval) {
              clearInterval(interval);
          }
      });
      this.waiters = [];
      return this;
  };
  
  /**
   * Sets the user-agent string currently used when requesting urls.
   *
   * @param  String  userAgent  User agent string
   * @return String
   */
  Casper.prototype.userAgent = function userAgent(agent) {
      "use strict";
      this.options.pageSettings.userAgent = agent;
      if (this.started && this.page) {
          this.page.settings.userAgent = agent;
      }
      return this;
  };
  
  /**
   * Changes the current viewport size. That operation is asynchronous as the page
   * has to reflow its contents accordingly.
   *
   * @param  Number    width   The viewport width, in pixels
   * @param  Number    height  The viewport height, in pixels
   * @param  Function  then    Next step to process (optional)
   * @return Casper
   */
  Casper.prototype.viewport = function viewport(width, height, then) {
      "use strict";
      this.checkStarted();
      if (!utils.isNumber(width) || !utils.isNumber(height) || width <= 0 || height <= 0) {
          throw new CasperError(f("Invalid viewport: %dx%d", width, height));
      }
  
      this.page.viewportSize = {
          width: width,
          height: height
      };
      // setting the viewport could cause a redraw and it can take
      // time. At least for Gecko, we should wait a bit, even
      // if this time could not be enough.
      var time = (phantom.casperEngine === 'slimerjs'?400:100);
      return this.then(function _step() {
          this.waitStart();
          setTimeout(function _check(self) {
              self.waitDone();
              self.emit('viewport.changed', [width, height]);
              if (utils.isFunction(then)){
                  self.then(then);
              }
          }, time, this);
      });
  };
  
  /**
   * Checks if an element matching the provided DOM CSS3/XPath selector is visible
   * current page DOM by checking that offsetWidth and offsetHeight are
   * both non-zero.
   *
   * @param  String  selector  A DOM CSS3/XPath selector
   * @return Boolean
   */
  Casper.prototype.visible = function visible(selector) {
      "use strict";
      this.checkStarted();
      return this.callUtils("visible", selector);
  };
  
  /**
   * Displays a warning message onto the console and logs the event. Also emits a
   * `warn` event with the message passed.
   *
   * @param  String  message
   * @return Casper
   */
  Casper.prototype.warn = function warn(message) {
      "use strict";
      this.log(message, "warning", "phantom");
      var formatted = f.apply(null, ["⚠  " + message].concat([].slice.call(arguments, 1)));
      this.emit('warn', message);
      return this.echo(formatted, 'COMMENT');
  };
  
  /**
   * Adds a new step that will wait for a given amount of time (expressed
   * in milliseconds) before processing an optional next one.
   *
   * @param  Number    timeout  The max amount of time to wait, in milliseconds
   * @param  Function  then     Next step to process (optional)
   * @return Casper
   */
  Casper.prototype.wait = function wait(timeout, then) {
      "use strict";
      this.checkStarted();
      timeout = ~~timeout;
      if (timeout < 1) {
          throw new CasperError("wait() only accepts a positive integer > 0 as a timeout value");
      }
      if (then && !utils.isFunction(then)) {
          throw new CasperError("wait() a step definition must be a function");
      }
      return this.then(function _step() {
          this.waitStart();
          setTimeout(function _check(self) {
              self.log(f("wait() finished waiting for %dms.", timeout), "info");
              if (then) {
                  try {
                      then.call(self, self);
                  } catch (error) {
                      self.emit('wait.error', error);
                      if (!self.options.silentErrors) {
                          throw error;
                      }
                  }
              }
              self.waitDone();
          }, timeout, this);
      });
  };
  
  Casper.prototype.waitStart = function waitStart() {
      "use strict";
      this.emit('wait.start');
      this.pendingWait = true;
  };
  
  Casper.prototype.waitDone = function waitDone() {
      "use strict";
      this.emit('wait.done');
      this.pendingWait = false;
  };
  
  /**
   * Waits until a function returns true to process a next step.
   *
   * @param  Function  testFx     A function to be evaluated for returning condition satisfecit
   * @param  Function  then       The next step to perform (optional)
   * @param  Function  onTimeout  A callback function to call on timeout (optional)
   * @param  Number    timeout    The max amount of time to wait, in milliseconds (optional)
   * @param  Object    details    A property bag of information about the condition being waited on (optional)
   * @return Casper
   */
  Casper.prototype.waitFor = function waitFor(testFx, then, onTimeout, timeout, details) {
      "use strict";
      this.checkStarted();
      timeout = timeout || this.options.waitTimeout;
      details = details || { testFx: testFx };
      if (!utils.isFunction(testFx)) {
          throw new CasperError("waitFor() needs a test function");
      }
      if (then && !utils.isFunction(then)) {
          throw new CasperError("waitFor() next step definition must be a function");
      }
      return this.then(function _step() {
          this.waitStart();
          var start = new Date().getTime();
          var condition = false;
          var interval = setInterval(function _check(self) {
              /*jshint maxstatements:20*/
              if ((new Date().getTime() - start < timeout) && !condition) {
                  condition = testFx.call(self, self);
                  return;
              }
              self.waitDone();
              if (!condition) {
                  self.log("Casper.waitFor() timeout", "warning");
                  var onWaitTimeout = onTimeout ? onTimeout : self.options.onWaitTimeout;
                  self.emit('waitFor.timeout', timeout, details);
                  clearInterval(interval); // refs #383
                  if (!utils.isFunction(onWaitTimeout)) {
                      throw new CasperError('Invalid timeout function');
                  }
                  try {
                      return onWaitTimeout.call(self, timeout, details);
                  } catch (error) {
                      self.emit('waitFor.timeout.error', error);
                      if (!self.options.silentErrors) {
                          throw error;
                      }
                  } finally {
                      return;
                  }
              }
              self.log(f("waitFor() finished in %dms.", new Date().getTime() - start), "info");
              clearInterval(interval);
              if (then) {
                  self.then(then);
              }
          }, this.options.retryTimeout, this);
          this.waiters.push(interval);
      });
  };
  
  /**
   * Waits until any alert is triggered.
   *
   * @param  Function  then       The next step to perform (required)
   * @param  Function  onTimeout  A callback function to call on timeout (optional)
   * @param  Number    timeout    The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitForAlert = function(then, onTimeout, timeout) {
      "use strict";
      if (!utils.isFunction(then)) {
          throw new CasperError("waitForAlert() needs a step function");
      }
      var message;
      function alertCallback(msg) {
          message = msg;
      }
      this.once("remote.alert", alertCallback);
      return this.waitFor(function isAlertReceived() {
          return message !== undefined;
      }, function onAlertReceived() {
          this.then(this.createStep(then, {data: message}));
      }, onTimeout, timeout);
  };
  
  /**
   * Waits for a popup page having its url matching the provided pattern to be opened
   * and loaded.
   *
   * @param  String|RegExp  urlPattern  The popup url pattern
   * @param  Function       then        The next step function (optional)
   * @param  Function       onTimeout   Function to call on operation timeout (optional)
   * @param  Number         timeout     Timeout in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitForPopup = function waitForPopup(urlPattern, then, onTimeout, timeout) {
      "use strict";
      return this.waitFor(function() {
          try {
              this.popups.find(urlPattern);
              return true;
          } catch (e) {
              return false;
          }
      }, then, onTimeout, timeout, { popup: urlPattern });
  };
  
  /**
   * Waits until a given resource is loaded
   *
   * @param  String/Function/RegExp  test       A function to test if the resource exists.
   *                                            A string will be matched against the resources url.
   * @param  Function                then       The next step to perform (optional)
   * @param  Function                onTimeout  A callback function to call on timeout (optional)
   * @param  Number                  timeout    The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitForResource = function waitForResource(test, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      return this.waitFor(function _check() {
          return this.resourceExists(test);
      }, then, onTimeout, timeout, { resource: test });
  };
  
  /**
   * Waits for a given url to be loaded.
   *
   * @param  String|RegExp  url  The url to wait for
   * @param  Function         then       The next step to perform (optional)
   * @param  Function         onTimeout  A callback function to call on timeout (optional)
   * @return Casper
   */
  Casper.prototype.waitForUrl = function waitForUrl(url, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      return this.waitFor(function _check() {
          if (utils.isString(url)) {
              return this.getCurrentUrl().indexOf(url) !== -1;
          } else if (utils.isRegExp(url)) {
              return url.test(this.getCurrentUrl());
          }
          throw new CasperError('invalid url argument');
      }, then, onTimeout, timeout, { url: url });
  };
  
  /**
   * Waits until an element matching the provided DOM CSS3/XPath selector exists in
   * remote DOM to process a next step.
   *
   * @param  String    selector   A DOM CSS3/XPath selector
   * @param  Function  then       The next step to perform (optional)
   * @param  Function  onTimeout  A callback function to call on timeout (optional)
   * @param  Number    timeout    The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitForSelector = function waitForSelector(selector, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      return this.waitFor(function _check() {
          return this.exists(selector);
      }, then, onTimeout, timeout, { selector: selector });
  };
  
  /**
   * Waits until the page contains given HTML text or matches a given RegExp.
   *
   * @param  String|RegExp  pattern    Text or RegExp to wait for
   * @param  Function       then       The next step to perform (optional)
   * @param  Function       onTimeout  A callback function to call on timeout (optional)
   * @param  Number         timeout    The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitForText = function(pattern, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      return this.waitFor(function _check() {
          var content = this.getPageContent();
          if (utils.isRegExp(pattern)) {
              return pattern.test(content);
          }
          return content.indexOf(pattern) !== -1;
      }, then, onTimeout, timeout, { text: pattern });
  };
  
  /**
   * Waits until the text on an element matching the provided DOM CSS3/XPath selector
   * is changed to a different value.
   *
   * @param String    selector    A DOM CSS3/XPath selector
   * @param Function  then        The next step to preform (optional)
   * @param Function  onTimeout   A callback function to call on timeout (optional)
   * @param Number    timeout     The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitForSelectorTextChange = function(selector, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      var currentSelectorText = this.fetchText(selector);
      return this.waitFor(function _check() {
          return currentSelectorText !== this.fetchText(selector);
      }, then, onTimeout, timeout, { selectorTextChange: selector });
  };
  
  /**
   * Waits until an element matching the provided DOM CSS3/XPath selector does not
   * exist in the remote DOM to process a next step.
   *
   * @param  String    selector   A DOM CSS3/XPath selector
   * @param  Function  then       The next step to perform (optional)
   * @param  Function  onTimeout  A callback function to call on timeout (optional)
   * @param  Number    timeout    The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitWhileSelector = function waitWhileSelector(selector, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      return this.waitFor(function _check() {
          return !this.exists(selector);
      }, then, onTimeout, timeout, {
          selector: selector,
          waitWhile: true
      });
  };
  
  /**
   * Waits until an element matching the provided DOM CSS3/XPath selector is
   * visible in the remote DOM to process a next step.
   *
   * @param  String    selector   A DOM CSS3/XPath selector
   * @param  Function  then       The next step to perform (optional)
   * @param  Function  onTimeout  A callback function to call on timeout (optional)
   * @param  Number    timeout    The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitUntilVisible = function waitUntilVisible(selector, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      return this.waitFor(function _check() {
          return this.visible(selector);
      }, then, onTimeout, timeout, { visible: selector });
  };
  
  /**
   * Waits until an element matching the provided DOM CSS3/XPath selector is no
   * longer visible in remote DOM to process a next step.
   *
   * @param  String    selector   A DOM CSS3/XPath selector
   * @param  Function  then       The next step to perform (optional)
   * @param  Function  onTimeout  A callback function to call on timeout (optional)
   * @param  Number    timeout    The max amount of time to wait, in milliseconds (optional)
   * @return Casper
   */
  Casper.prototype.waitWhileVisible = function waitWhileVisible(selector, then, onTimeout, timeout) {
      "use strict";
      this.checkStarted();
      timeout = timeout ? timeout : this.options.waitTimeout;
      return this.waitFor(function _check() {
          return !this.visible(selector);
      }, then, onTimeout, timeout, {
          visible: selector,
          waitWhile: true
      });
  };
  
  /**
   * Makes the provided frame page as the currently active one. Note that the
   * active page will be reverted when finished.
   *
   * @param  String|Number    frameInfo  Target frame name or number
   * @param  Function  then       Next step function
   * @return Casper
   */
  Casper.prototype.withFrame = function withFrame(frameInfo, then) {
      "use strict";
      this.then(function _step() {
          if (utils.isNumber(frameInfo)) {
              if (frameInfo > this.page.childFramesCount() - 1) {
                  throw new CasperError(f('Frame number "%d" is out of bounds.', frameInfo));
              }
          } else if (this.page.childFramesName().indexOf(frameInfo) === -1) {
              throw new CasperError(f('No frame named "%s" was found.', frameInfo));
          }
          // make the frame page the currently active one
          this.page.switchToChildFrame(frameInfo);
      });
      try {
          this.then(then);
      } catch (e) {
          // revert to main page on error
          this.warn("Error while processing frame step: " + e);
          this.page.switchToParentFrame();
          throw e;
      }
      return this.then(function _step() {
          // revert to main page
          this.page.switchToParentFrame();
      });
  };
  
  /**
   * Makes the provided frame page as the currently active one. Note that the
   * active page will be reverted when finished.
   *
   * @param  String|RegExp|WebPage  popup  Target frame page information
   * @param  Function               then   Next step function
   * @return Casper
   */
  Casper.prototype.withPopup = function withPopup(popupInfo, then) {
      "use strict";
      this.then(function _step() {
          var popupPage = this.popups.find(popupInfo);
          if (!utils.isFunction(then)) {
              throw new CasperError("withPopup() requires a step function.");
          }
          // make the popup page the currently active one
          this.page = popupPage;
      });
      try {
          this.then(then);
      } catch (e) {
          // revert to main page on error
          this.log("error while processing popup step: " + e, "error");
          this.page = this.mainPage;
          throw e;
      }
      return this.then(function _step() {
          // revert to main page
          this.page = this.mainPage;
      });
  };
  
  /**
   * Changes the current page zoom factor.
   *
   * @param  Number  factor  The zoom factor
   * @return Casper
   */
  Casper.prototype.zoom = function zoom(factor) {
      "use strict";
      this.checkStarted();
      if (!utils.isNumber(factor) || factor <= 0) {
          throw new CasperError("Invalid zoom factor: " + factor);
      }
      this.page.zoomFactor = factor;
      return this;
  };
  
  /**
   * Extends Casper's prototype with provided one.
   *
   * @param  Object  proto  Prototype methods to add to Casper
   * @deprecated
   * @since 0.6
   */
  Casper.extend = function(proto) {
      "use strict";
      this.emit("deprecated", "Casper.extend() has been deprecated since 0.6; check the docs")
      if (!utils.isObject(proto)) {
          throw new CasperError("extends() only accept objects as prototypes");
      }
      utils.mergeObjects(Casper.prototype, proto);
  };
  
  exports.Casper = Casper;
  
  /**
   * Creates a new WebPage instance for Casper use.
   *
   * @param  Casper  casper  A Casper instance
   * @return WebPage
   */
  function createPage(casper) {
      /*jshint maxstatements:20*/
      "use strict";
      var page = require('webpage').create();
      page.onAlert = function onAlert(message) {
          casper.log('[alert] ' + message, "info", "remote");
          casper.emit('remote.alert', message);
          if (utils.isFunction(casper.options.onAlert)) {
              casper.options.onAlert.call(casper, casper, message);
          }
      };
      page.onConfirm = function onConfirm(message) {
          if ('page.confirm' in casper._filters) {
              return casper.filter('page.confirm', message);
          }
          return true;
      };
      page.onConsoleMessage = function onConsoleMessage(msg) {
          // client utils casper console message
          var consoleTest = /^\[casper\.echo\]\s?([\s\S]*)/.exec(msg);
          if (consoleTest && consoleTest.length === 2) {
              casper.echo(consoleTest[1]);
              return; // don't trigger remote.message event for these
          }
          // client utils log messages
          var logLevel = "info",
              logTest = /^\[casper:(\w+)\]\s?([\s\S]*)/m.exec(msg);
          if (logTest && logTest.length === 3) {
              logLevel = logTest[1];
              msg = logTest[2];
              casper.log(msg, logLevel, "remote");
          } else {
              casper.emit('remote.message', msg);
          }
      };
  
      page.onCallback = function onCallback(data){
          casper.emit('remote.callback',data);
      };
  
      page.onError = function onError(msg, trace) {
          casper.emit('page.error', msg, trace);
      };
      page.onInitialized = function onInitialized() {
          casper.emit('page.initialized', page);
          if (utils.isFunction(casper.options.onPageInitialized)) {
              casper.log("Post-configuring WebPage instance", "debug");
              casper.options.onPageInitialized.call(casper, page);
          }
      };
      page.onLoadStarted = function onLoadStarted() {
          // in some case, there is no navigation requested event, so
          // be sure that browserInitializing is false to not block checkStep()
          casper.browserInitializing = false;
          casper.loadInProgress = true;
          casper.emit('load.started');
      };
      page.onLoadFinished = function onLoadFinished(status) {
          /*jshint maxstatements:20*/
          if (status !== "success") {
              casper.emit('load.failed', {
                  status:      status,
                  http_status: casper.currentHTTPStatus,
                  url:         casper.requestUrl
              });
              var message = 'Loading resource failed with status=' + status;
              if (casper.currentHTTPStatus) {
                  message += f(' (HTTP %d)', casper.currentHTTPStatus);
              }
              message += ': ' + casper.requestUrl;
              casper.log(message, "warning");
              casper.navigationRequested = false;
              casper.browserInitializing = false;
              if (utils.isFunction(casper.options.onLoadError)) {
                  casper.options.onLoadError.call(casper, casper, casper.requestUrl, status);
              }
          }
          // local client scripts
          casper.injectClientScripts();
          // remote client scripts
          casper.includeRemoteScripts();
          // Client-side utils injection
          casper.injectClientUtils();
          // history
          casper.history.push(casper.getCurrentUrl());
          casper.emit('load.finished', status);
          casper.loadInProgress = false;
      };
      page.onNavigationRequested = function onNavigationRequested(url, type, willNavigate, isMainFrame) {
          casper.log(f('Navigation requested: url=%s, type=%s, willNavigate=%s, isMainFrame=%s',
                       url, type, willNavigate, isMainFrame), "debug");
          casper.browserInitializing = false;
          if (isMainFrame && casper.requestUrl !== url) {
              var currentUrl = casper.requestUrl;
              var newUrl = url;
              var pos = currentUrl.indexOf('#')
              if (pos !== -1) {
                  currentUrl = currentUrl.substring(0, pos);
              }
              pos = newUrl.indexOf('#')
              if (pos !== -1) {
                  newUrl = newUrl.substring(0, pos);
              }
              // for URLs that are only different by their hash part
              // or if navigation locked (willNavigate == false)
              // don't turn navigationRequested to true, because
              // there will not be loadStarted, loadFinished events
              // so it could cause issues (for exemple, checkStep that
              // do no execute the next step -> infinite loop on checkStep)
              if (willNavigate && currentUrl !== newUrl)
                  casper.navigationRequested  = true;
  
              if (willNavigate) {
                  casper.requestUrl = url;
              }
          }
          casper.emit('navigation.requested', url, type, willNavigate, isMainFrame);
      };
      page.onPageCreated = function onPageCreated(popupPage) {
          casper.emit('popup.created', popupPage);
          popupPage.onLoadFinished = function onLoadFinished() {
              // SlimerJS needs this line of code because of issue
              // https://github.com/laurentj/slimerjs/issues/48
              // else checkStep turns into an infinite loop
              // after clicking on an <a target="_blank">
              casper.navigationRequested  = false;
              casper.popups.push(popupPage);
              casper.emit('popup.loaded', popupPage);
          };
          popupPage.onClosing = function onClosing(closedPopup) {
              casper.popups.clean(closedPopup);
              casper.emit('popup.closed', closedPopup);
          };
      };
      page.onPrompt = function onPrompt(message, value) {
          return casper.filter('page.prompt', message, value);
      };
      page.onResourceReceived = function onResourceReceived(resource) {
          http.augmentResponse(resource);
          casper.emit('resource.received', resource);
          if (utils.isFunction(casper.options.onResourceReceived)) {
              casper.options.onResourceReceived.call(casper, casper, resource);
          }
          casper.handleReceivedResource(resource);
      };
      page.onResourceRequested = function onResourceRequested(requestData, request) {
          casper.emit('resource.requested', requestData, request);
          if (requestData.url === casper.requestUrl) {
              casper.emit('page.resource.requested', requestData, request);
          }
          if (utils.isFunction(casper.options.onResourceRequested)) {
              casper.options.onResourceRequested.call(casper, casper, requestData, request);
          }
      };
      page.onResourceError = function onResourceError(resourceError) {
          casper.emit('resource.error', resourceError);
      };
      page.onUrlChanged = function onUrlChanged(url) {
          casper.log(f('url changed to "%s"', url), "debug");
          casper.navigationRequested = false;
          casper.emit('url.changed', url);
      };
      casper.emit('page.created', page);
      return page;
  }
  