text: // jquery.pjax.js
  // copyright chris wanstrath
  // https://github.com/defunkt/jquery-pjax
  
  (function($){
  function fnPjax(selector, container, options) {
    var context = this
    return this.on('click.pjax', selector, function(event) {
      var opts = $.extend({}, optionsFor(container, options))
      if (!opts.container)
        opts.container = $(this).attr('data-pjax') || context
      handleClick(event, opts)
    })
  }
  
  function handleClick(event, container, options) {
    options = optionsFor(container, options)
  
    var link = event.currentTarget
  
    if (link.tagName.toUpperCase() !== 'A')
      throw "$.fn.pjax or $.pjax.click requires an anchor element"
  
    // Middle click, cmd click, and ctrl click should open
    // links in a new tab as normal.
    if ( event.which > 1 || event.metaKey || event.ctrlKey || event.shiftKey || event.altKey )
      return
  
    // Ignore cross origin links
    if ( location.protocol !== link.protocol || location.hostname !== link.hostname )
      return
  
    // Ignore anchors on the same page
    if (link.hash && link.href.replace(link.hash, '') ===
         location.href.replace(location.hash, ''))
      return
  
    // Ignore empty anchor "foo.html#"
    if (link.href === location.href + '#')
      return
  
    var defaults = {
      url: link.href,
      container: $(link).attr('data-pjax'),
      target: link
    }
  
    var opts = $.extend({}, defaults, options)
    var clickEvent = $.Event('pjax:click')
    $(link).trigger(clickEvent, [opts])
  
    if (!clickEvent.isDefaultPrevented()) {
      pjax(opts)
      event.preventDefault()
      $(link).trigger('pjax:clicked', [opts])
    }
  }
  
  // Public: pjax on form submit handler
  //
  // Exported as $.pjax.submit
  //
  // event   - "click" jQuery.Event
  // options - pjax options
  //
  // Examples
  //
  //  $(document).on('submit', 'form', function(event) {
  //    var container = $(this).closest('[data-pjax-container]')
  //    $.pjax.submit(event, container)
  //  })
  //
  // Returns nothing.
  function handleSubmit(event, container, options) {
    options = optionsFor(container, options)
  
    var form = event.currentTarget
  
    if (form.tagName.toUpperCase() !== 'FORM')
      throw "$.pjax.submit requires a form element"
  
    var defaults = {
      type: form.method.toUpperCase(),
      url: form.action,
      data: $(form).serializeArray(),
      container: $(form).attr('data-pjax'),
      target: form
    }
  
    pjax($.extend({}, defaults, options))
  
    event.preventDefault()
  }
  
  // Loads a URL with ajax, puts the response body inside a container,
  // then pushState()'s the loaded URL.
  //
  // Works just like $.ajax in that it accepts a jQuery ajax
  // settings object (with keys like url, type, data, etc).
  //
  // Accepts these extra keys:
  //
  // container - Where to stick the response body.
  //             $(container).html(xhr.responseBody)
  //      push - Whether to pushState the URL. Defaults to true (of course).
  //   replace - Want to use replaceState instead? That's cool.
  //
  // Use it just like $.ajax:
  //
  //   var xhr = $.pjax({ url: this.href, container: '#main' })
  //   console.log( xhr.readyState )
  //
  // Returns whatever $.ajax returns.
  function pjax(options) {
    options = $.extend(true, {}, $.ajaxSettings, pjax.defaults, options)
  
    if ($.isFunction(options.url)) {
      options.url = options.url()
    }
  
    var target = options.target
  
    var hash = parseURL(options.url).hash
  
    var context = options.context = findContainerFor(options.container)
  
    // We want the browser to maintain two separate internal caches: one
    // for pjax'd partial page loads and one for normal page loads.
    // Without adding this secret parameter, some browsers will often
    // confuse the two.
    if (!options.data) options.data = {}
    options.data._pjax = context.selector
  
    function fire(type, args) {
      var event = $.Event(type, { relatedTarget: target })
      context.trigger(event, args)
      return !event.isDefaultPrevented()
    }
  
    var timeoutTimer
  
    options.beforeSend = function(xhr, settings) {
      // No timeout for non-GET requests
      // Its not safe to request the resource again with a fallback method.
      if (settings.type !== 'GET') {
        settings.timeout = 0
      }
  
      xhr.setRequestHeader('X-PJAX', 'true')
      xhr.setRequestHeader('X-PJAX-Container', context.selector)
  
      if (!fire('pjax:beforeSend', [xhr, settings]))
        return false
  
      if (settings.timeout > 0) {
        timeoutTimer = setTimeout(function() {
          if (fire('pjax:timeout', [xhr, options]))
            xhr.abort('timeout')
        }, settings.timeout)
  
        // Clear timeout setting so jquerys internal timeout isn't invoked
        settings.timeout = 0
      }
  
      options.requestUrl = parseURL(settings.url).href
    }
  
    options.complete = function(xhr, textStatus) {
      if (timeoutTimer)
        clearTimeout(timeoutTimer)
  
      fire('pjax:complete', [xhr, textStatus, options])
  
      fire('pjax:end', [xhr, options])
    }
  
    options.error = function(xhr, textStatus, errorThrown) {
      var container = extractContainer("", xhr, options)
  
      var allowed = fire('pjax:error', [xhr, textStatus, errorThrown, options])
      if (options.type == 'GET' && textStatus !== 'abort' && allowed) {
        locationReplace(container.url)
      }
    }
  
    options.success = function(data, status, xhr) {
      // If $.pjax.defaults.version is a function, invoke it first.
      // Otherwise it can be a static string.
      var currentVersion = (typeof $.pjax.defaults.version === 'function') ?
        $.pjax.defaults.version() :
        $.pjax.defaults.version
  
      var latestVersion = xhr.getResponseHeader('X-PJAX-Version')
  
      var container = extractContainer(data, xhr, options)
  
      // If there is a layout version mismatch, hard load the new url
      if (currentVersion && latestVersion && currentVersion !== latestVersion) {
        locationReplace(container.url)
        return
      }
  
      // If the new response is missing a body, hard load the page
      if (!container.contents) {
        locationReplace(container.url)
        return
      }
  
      pjax.state = {
        id: options.id || uniqueId(),
        url: container.url,
        title: container.title,
        container: context.selector,
        fragment: options.fragment,
        timeout: options.timeout
      }
  
      if (options.push || options.replace) {
        window.history.replaceState(pjax.state, container.title, container.url)
      }
  
      // Clear out any focused controls before inserting new page contents.
      document.activeElement.blur()
  
      if (container.title) document.title = container.title
      context.html(container.contents)
  
      // FF bug: Won't autofocus fields that are inserted via JS.
      // This behavior is incorrect. So if theres no current focus, autofocus
      // the last field.
      //
      // http://www.w3.org/html/wg/drafts/html/master/forms.html
      var autofocusEl = context.find('input[autofocus], textarea[autofocus]').last()[0]
      if (autofocusEl && document.activeElement !== autofocusEl) {
        autofocusEl.focus();
      }
  
      executeScriptTags(container.scripts)
  
      // Scroll to top by default
      if (typeof options.scrollTo === 'number')
        $(window).scrollTop(options.scrollTo)
  
      // If the URL has a hash in it, make sure the browser
      // knows to navigate to the hash.
      if ( hash !== '' ) {
        // Avoid using simple hash set here. Will add another history
        // entry. Replace the url with replaceState and scroll to target
        // by hand.
        //
        //   window.location.hash = hash
        var url = parseURL(container.url)
        url.hash = hash
  
        pjax.state.url = url.href
        window.history.replaceState(pjax.state, container.title, url.href)
  
        var target = $(url.hash)
        if (target.length) $(window).scrollTop(target.offset().top)
      }
  
      fire('pjax:success', [data, status, xhr, options])
    }
  
  
    // Initialize pjax.state for the initial page load. Assume we're
    // using the container and options of the link we're loading for the
    // back button to the initial page. This ensures good back button
    // behavior.
    if (!pjax.state) {
      pjax.state = {
        id: uniqueId(),
        url: window.location.href,
        title: document.title,
        container: context.selector,
        fragment: options.fragment,
        timeout: options.timeout
      }
      window.history.replaceState(pjax.state, document.title)
    }
  
    // Cancel the current request if we're already pjaxing
    var xhr = pjax.xhr
    if ( xhr && xhr.readyState < 4) {
      xhr.onreadystatechange = $.noop
      xhr.abort()
    }
  
    pjax.options = options
    var xhr = pjax.xhr = $.ajax(options)
  
    if (xhr.readyState > 0) {
      if (options.push && !options.replace) {
        // Cache current container element before replacing it
        cachePush(pjax.state.id, context.clone().contents())
  
        window.history.pushState(null, "", stripPjaxParam(options.requestUrl))
      }
  
      fire('pjax:start', [xhr, options])
      fire('pjax:send', [xhr, options])
    }
  
    return pjax.xhr
  }
  
  // Public: Reload current page with pjax.
  //
  // Returns whatever $.pjax returns.
  function pjaxReload(container, options) {
    var defaults = {
      url: window.location.href,
      push: false,
      replace: true,
      scrollTo: false
    }
  
    return pjax($.extend(defaults, optionsFor(container, options)))
  }
  
  // Internal: Hard replace current state with url.
  //
  // Work for around WebKit
  //   https://bugs.webkit.org/show_bug.cgi?id=93506
  //
  // Returns nothing.
  function locationReplace(url) {
    window.history.replaceState(null, "", "#")
    window.location.replace(url)
  }
  
  
  var initialPop = true
  var initialURL = window.location.href
  var initialState = window.history.state
  
  // Initialize $.pjax.state if possible
  // Happens when reloading a page and coming forward from a different
  // session history.
  if (initialState && initialState.container) {
    pjax.state = initialState
  }
  
  // Non-webkit browsers don't fire an initial popstate event
  if ('state' in window.history) {
    initialPop = false
  }
  
  // popstate handler takes care of the back and forward buttons
  //
  // You probably shouldn't use pjax on pages with other pushState
  // stuff yet.
  function onPjaxPopstate(event) {
    var state = event.state
  
    if (state && state.container) {
      // When coming forward from a separate history session, will get an
      // initial pop with a state we are already at. Skip reloading the current
      // page.
      if (initialPop && initialURL == state.url) return
  
      // If popping back to the same state, just skip.
      // Could be clicking back from hashchange rather than a pushState.
      if (pjax.state.id === state.id) return
  
      var container = $(state.container)
      if (container.length) {
        var direction, contents = cacheMapping[state.id]
  
        if (pjax.state) {
          // Since state ids always increase, we can deduce the history
          // direction from the previous state.
          direction = pjax.state.id < state.id ? 'forward' : 'back'
  
          // Cache current container before replacement and inform the
          // cache which direction the history shifted.
          cachePop(direction, pjax.state.id, container.clone().contents())
        }
  
        var popstateEvent = $.Event('pjax:popstate', {
          state: state,
          direction: direction
        })
        container.trigger(popstateEvent)
  
        var options = {
          id: state.id,
          url: state.url,
          container: container,
          push: false,
          fragment: state.fragment,
          timeout: state.timeout,
          scrollTo: false
        }
  
        if (contents) {
          container.trigger('pjax:start', [null, options])
  
          if (state.title) document.title = state.title
          container.html(contents)
          pjax.state = state
  
          container.trigger('pjax:end', [null, options])
        } else {
          pjax(options)
        }
  
        // Force reflow/relayout before the browser tries to restore the
        // scroll position.
        container[0].offsetHeight
      } else {
        locationReplace(location.href)
      }
    }
    initialPop = false
  }
  
  // Fallback version of main pjax function for browsers that don't
  // support pushState.
  //
  // Returns nothing since it retriggers a hard form submission.
  function fallbackPjax(options) {
    var url = $.isFunction(options.url) ? options.url() : options.url,
        method = options.type ? options.type.toUpperCase() : 'GET'
  
    var form = $('<form>', {
      method: method === 'GET' ? 'GET' : 'POST',
      action: url,
      style: 'display:none'
    })
  
    if (method !== 'GET' && method !== 'POST') {
      form.append($('<input>', {
        type: 'hidden',
        name: '_method',
        value: method.toLowerCase()
      }))
    }
  
    var data = options.data
    if (typeof data === 'string') {
      $.each(data.split('&'), function(index, value) {
        var pair = value.split('=')
        form.append($('<input>', {type: 'hidden', name: pair[0], value: pair[1]}))
      })
    } else if (typeof data === 'object') {
      for (key in data)
        form.append($('<input>', {type: 'hidden', name: key, value: data[key]}))
    }
  
    $(document.body).append(form)
    form.submit()
  }
  
  // Internal: Generate unique id for state object.
  //
  // Use a timestamp instead of a counter since ids should still be
  // unique across page loads.
  //
  // Returns Number.
  function uniqueId() {
    return (new Date).getTime()
  }
  
  // Internal: Strips _pjax param from url
  //
  // url - String
  //
  // Returns String.
  function stripPjaxParam(url) {
    return url
      .replace(/\?_pjax=[^&]+&?/, '?')
      .replace(/_pjax=[^&]+&?/, '')
      .replace(/[\?&]$/, '')
  }
  
  // Internal: Parse URL components and returns a Locationish object.
  //
  // url - String URL
  //
  // Returns HTMLAnchorElement that acts like Location.
  function parseURL(url) {
    var a = document.createElement('a')
    a.href = url
    return a
  }
  
  // Internal: Build options Object for arguments.
  //
  // For convenience the first parameter can be either the container or
  // the options object.
  //
  // Examples
  //
  //   optionsFor('#container')
  //   // => {container: '#container'}
  //
  //   optionsFor('#container', {push: true})
  //   // => {container: '#container', push: true}
  //
  //   optionsFor({container: '#container', push: true})
  //   // => {container: '#container', push: true}
  //
  // Returns options Object.
  function optionsFor(container, options) {
    // Both container and options
    if ( container && options )
      options.container = container
  
    // First argument is options Object
    else if ( $.isPlainObject(container) )
      options = container
  
    // Only container
    else
      options = {container: container}
  
    // Find and validate container
    if (options.container)
      options.container = findContainerFor(options.container)
  
    return options
  }
  
  // Internal: Find container element for a variety of inputs.
  //
  // Because we can't persist elements using the history API, we must be
  // able to find a String selector that will consistently find the Element.
  //
  // container - A selector String, jQuery object, or DOM Element.
  //
  // Returns a jQuery object whose context is `document` and has a selector.
  function findContainerFor(container) {
    container = $(container)
  
    if ( !container.length ) {
      throw "no pjax container for " + container.selector
    } else if ( container.selector !== '' && container.context === document ) {
      return container
    } else if ( container.attr('id') ) {
      return $('#' + container.attr('id'))
    } else {
      throw "cant get selector for pjax container!"
    }
  }
  
  // Internal: Filter and find all elements matching the selector.
  //
  // Where $.fn.find only matches descendants, findAll will test all the
  // top level elements in the jQuery object as well.
  //
  // elems    - jQuery object of Elements
  // selector - String selector to match
  //
  // Returns a jQuery object.
  function findAll(elems, selector) {
    return elems.filter(selector).add(elems.find(selector));
  }
  
  function parseHTML(html) {
    return $.parseHTML(html, document, true)
  }
  
  // Internal: Extracts container and metadata from response.
  //
  // 1. Extracts X-PJAX-URL header if set
  // 2. Extracts inline <title> tags
  // 3. Builds response Element and extracts fragment if set
  //
  // data    - String response data
  // xhr     - XHR response
  // options - pjax options Object
  //
  // Returns an Object with url, title, and contents keys.
  function extractContainer(data, xhr, options) {
    var obj = {}
  
    // Prefer X-PJAX-URL header if it was set, otherwise fallback to
    // using the original requested url.
    obj.url = stripPjaxParam(xhr.getResponseHeader('X-PJAX-URL') || options.requestUrl)
  
    // Attempt to parse response html into elements
    if (/<html/i.test(data)) {
      var $head = $(parseHTML(data.match(/<head[^>]*>([\s\S.]*)<\/head>/i)[0]))
      var $body = $(parseHTML(data.match(/<body[^>]*>([\s\S.]*)<\/body>/i)[0]))
    } else {
      var $head = $body = $(parseHTML(data))
    }
  
    // If response data is empty, return fast
    if ($body.length === 0)
      return obj
  
    // If there's a <title> tag in the header, use it as
    // the page's title.
    obj.title = findAll($head, 'title').last().text()
  
    if (options.fragment) {
      // If they specified a fragment, look for it in the response
      // and pull it out.
      if (options.fragment === 'body') {
        var $fragment = $body
      } else {
        var $fragment = findAll($body, options.fragment).first()
      }
  
      if ($fragment.length) {
        obj.contents = $fragment.contents()
  
        // If there's no title, look for data-title and title attributes
        // on the fragment
        if (!obj.title)
          obj.title = $fragment.attr('title') || $fragment.data('title')
      }
  
    } else if (!/<html/i.test(data)) {
      obj.contents = $body
    }
  
    // Clean up any <title> tags
    if (obj.contents) {
      // Remove any parent title elements
      obj.contents = obj.contents.not(function() { return $(this).is('title') })
  
      // Then scrub any titles from their descendants
      obj.contents.find('title').remove()
  
      // Gather all script[src] elements
      obj.scripts = findAll(obj.contents, 'script[src]').remove()
      obj.contents = obj.contents.not(obj.scripts)
    }
  
    // Trim any whitespace off the title
    if (obj.title) obj.title = $.trim(obj.title)
  
    return obj
  }
  
  // Load an execute scripts using standard script request.
  //
  // Avoids jQuery's traditional $.getScript which does a XHR request and
  // globalEval.
  //
  // scripts - jQuery object of script Elements
  //
  // Returns nothing.
  function executeScriptTags(scripts) {
    if (!scripts) return
  
    var existingScripts = $('script[src]')
  
    scripts.each(function() {
      var src = this.src
      var matchedScripts = existingScripts.filter(function() {
        return this.src === src
      })
      if (matchedScripts.length) return
  
      var script = document.createElement('script')
      script.type = $(this).attr('type')
      script.src = $(this).attr('src')
      document.head.appendChild(script)
    })
  }
  
  // Internal: History DOM caching class.
  var cacheMapping      = {}
  var cacheForwardStack = []
  var cacheBackStack    = []
  
  // Push previous state id and container contents into the history
  // cache. Should be called in conjunction with `pushState` to save the
  // previous container contents.
  //
  // id    - State ID Number
  // value - DOM Element to cache
  //
  // Returns nothing.
  function cachePush(id, value) {
    cacheMapping[id] = value
    cacheBackStack.push(id)
  
    // Remove all entires in forward history stack after pushing
    // a new page.
    while (cacheForwardStack.length)
      delete cacheMapping[cacheForwardStack.shift()]
  
    // Trim back history stack to max cache length.
    while (cacheBackStack.length > pjax.defaults.maxCacheLength)
      delete cacheMapping[cacheBackStack.shift()]
  }
  
  // Shifts cache from directional history cache. Should be
  // called on `popstate` with the previous state id and container
  // contents.
  //
  // direction - "forward" or "back" String
  // id        - State ID Number
  // value     - DOM Element to cache
  //
  // Returns nothing.
  function cachePop(direction, id, value) {
    var pushStack, popStack
    cacheMapping[id] = value
  
    if (direction === 'forward') {
      pushStack = cacheBackStack
      popStack  = cacheForwardStack
    } else {
      pushStack = cacheForwardStack
      popStack  = cacheBackStack
    }
  
    pushStack.push(id)
    if (id = popStack.pop())
      delete cacheMapping[id]
  }
  
  // Public: Find version identifier for the initial page load.
  //
  // Returns String version or undefined.
  function findVersion() {
    return $('meta').filter(function() {
      var name = $(this).attr('http-equiv')
      return name && name.toUpperCase() === 'X-PJAX-VERSION'
    }).attr('content')
  }
  
  // Install pjax functions on $.pjax to enable pushState behavior.
  //
  // Does nothing if already enabled.
  //
  // Examples
  //
  //     $.pjax.enable()
  //
  // Returns nothing.
  function enable() {
    $.fn.pjax = fnPjax
    $.pjax = pjax
    $.pjax.enable = $.noop
    $.pjax.disable = disable
    $.pjax.click = handleClick
    $.pjax.submit = handleSubmit
    $.pjax.reload = pjaxReload
    $.pjax.defaults = {
      timeout: 8000,
      push: true,
      replace: false,
      type: 'GET',
      dataType: 'html',
      scrollTo: 0,
      maxCacheLength: 200,
      version: findVersion
    }
    $(window).on('popstate.pjax', onPjaxPopstate)
  }
  
  // Disable pushState behavior.
  //
  // This is the case when a browser doesn't support pushState. It is
  // sometimes useful to disable pushState for debugging on a modern
  // browser.
  //
  // Examples
  //
  //     $.pjax.disable()
  //
  // Returns nothing.
  function disable() {
    $.fn.pjax = function() { return this }
    $.pjax = fallbackPjax
    $.pjax.enable = enable
    $.pjax.disable = $.noop
    $.pjax.click = $.noop
    $.pjax.submit = $.noop
    $.pjax.reload = function() { window.location.reload() }
  
    $(window).off('popstate.pjax', onPjaxPopstate)
  }
  
  
  // Add the state property to jQuery's event object so we can use it in
  // $(window).bind('popstate')
  if ( $.inArray('state', $.event.props) < 0 )
    $.event.props.push('state')
  
  // Is pjax supported by this browser?
  $.support.pjax =
    window.history && window.history.pushState && window.history.replaceState &&
    // pushState isn't reliable on iOS until 5.
    !navigator.userAgent.match(/((iPod|iPhone|iPad).+\bOS\s+[1-4]|WebApps\/.+CFNetwork)/)
  
  $.support.pjax ? enable() : disable()
  
  })(jQuery);