text: ﻿/*
  * Lazy Load - jQuery plugin for lazy loading images
  *
  * Copyright (c) 2007-2012 Mika Tuupola
  *
  * Licensed under the MIT license:
  *   http://www.opensource.org/licenses/mit-license.php
  *
  * Project home:
  *   http://www.appelsiini.net/projects/lazyload
  *
  * Version:  1.7.2
  *
  */
  (function($, window) {
  
      $window = $(window);
  
      $.fn.lazyload = function(options) {
          var elements = this;
          var settings = {
              threshold: 0,
              failure_limit: 0,
              event: "scroll",
              effect: "fadeIn",
              container: window,
              data_attribute: "original",
              skip_invisible: true,
              appear: null,
              load: null
          };       
          function update() {
              var counter = 0;
  
              elements.each(function() {
                  var $this = $(this);
                  if (settings.skip_invisible && !$this.is(":visible")) {
                      return;
                  }
                  if ($.abovethetop(this, settings) ||
                      $.leftofbegin(this, settings)) {
                      /* Nothing. */
                  } else if (!$.belowthefold(this, settings) &&
                      !$.rightoffold(this, settings)) {
                      $this.trigger("appear");
                  } else {
                      if (++counter > settings.failure_limit) {
                          return false;
                      }
                  }
              });
  
          }
  
          if (options) {
              /* Maintain BC for a couple of versions. */
              if (undefined !== options.failurelimit) {
                  options.failure_limit = options.failurelimit;
                  delete options.failurelimit;
              }
              if (undefined !== options.effectspeed) {
                  options.effect_speed = options.effectspeed;
                  delete options.effectspeed;
              }
  
              $.extend(settings, options);
          }
  
          /* Cache container as jQuery as object. */
          $container = (settings.container === undefined ||
                        settings.container === window) ? $window : $(settings.container);
  
          /* Fire one scroll event per scroll. Not one scroll event per image. */
          if (0 === settings.event.indexOf("scroll")) {
              $container.bind(settings.event, function(event) {
                  return update();
              });
          }
  
          this.each(function() {
              var self = this;
              var $self = $(self);
  
              self.loaded = false;
  
              /* When appear is triggered load original image. */
              $self.one("appear", function() {
                  if (!this.loaded) {
                      if (settings.appear) {
                          var elements_left = elements.length;
                          settings.appear.call(self, elements_left, settings);
                      }
                      $("<img />")
                          .bind("load", function() {
                              $self
                                  .hide()
                                  .attr("src", $self.data(settings.data_attribute))
                                  [settings.effect](settings.effect_speed);
                              self.loaded = true;
  
                              /* Remove image from array so it is not looped next time. */
                              var temp = $.grep(elements, function(element) {
                                  return !element.loaded;
                              });
                              elements = $(temp);
  
                              if (settings.load) {
                                  var elements_left = elements.length;
                                  settings.load.call(self, elements_left, settings);
                              }
                          })
                          .attr("src", $self.data(settings.data_attribute));
                  }
              });
  
              /* When wanted event is triggered load original image */
              /* by triggering appear.                              */
              if (0 !== settings.event.indexOf("scroll")) {
                  $self.bind(settings.event, function(event) {
                      if (!self.loaded) {
                          $self.trigger("appear");
                      }
                  });
              }
          });
  
          /* Check if something appears when window is resized. */
          $window.bind("resize", function(event) {
              update();
          });
  
          /* Force initial check if images should appear. */
          update();
  
          return this;
      };
  
      /* Convenience methods in jQuery namespace.           */
      /* Use as  $.belowthefold(element, {threshold : 100, container : window}) */
  
      $.belowthefold = function(element, settings) {
          var fold;
  
          if (settings.container === undefined || settings.container === window) {
              fold = $window.height() + $window.scrollTop();
          } else {
              fold = $container.offset().top + $container.height();
          }
  
          return fold <= $(element).offset().top - settings.threshold;
      };
  
      $.rightoffold = function(element, settings) {
          var fold;
  
          if (settings.container === undefined || settings.container === window) {
              fold = $window.width() + $window.scrollLeft();
          } else {
              fold = $container.offset().left + $container.width();
          }
  
          return fold <= $(element).offset().left - settings.threshold;
      };
  
      $.abovethetop = function(element, settings) {
          var fold;
  
          if (settings.container === undefined || settings.container === window) {
              fold = $window.scrollTop();
          } else {
              fold = $container.offset().top;
          }
  
          return fold >= $(element).offset().top + settings.threshold + $(element).height();
      };
  
      $.leftofbegin = function(element, settings) {
          var fold;
  
          if (settings.container === undefined || settings.container === window) {
              fold = $window.scrollLeft();
          } else {
              fold = $container.offset().left;
          }
  
          return fold >= $(element).offset().left + settings.threshold + $(element).width();
      };
  
      $.inviewport = function(element, settings) {
          return !$.rightofscreen(element, settings) && !$.leftofscreen(element, settings) &&
                  !$.belowthefold(element, settings) && !$.abovethetop(element, settings);
      };
  
      /* Custom selectors for your convenience.   */
      /* Use as $("img:below-the-fold").something() */
  
      $.extend($.expr[':'], {
          "below-the-fold": function(a) { return $.belowthefold(a, { threshold: 0, container: window }); },
          "above-the-top": function(a) { return !$.belowthefold(a, { threshold: 0, container: window }); },
          "right-of-screen": function(a) { return $.rightoffold(a, { threshold: 0, container: window }); },
          "left-of-screen": function(a) { return !$.rightoffold(a, { threshold: 0, container: window }); },
          "in-viewport": function(a) { return !$.inviewport(a, { threshold: 0, container: window }); },
          /* Maintain BC for couple of versions. */
          "above-the-fold": function(a) { return !$.belowthefold(a, { threshold: 0, container: window }); },
          "right-of-fold": function(a) { return $.rightoffold(a, { threshold: 0, container: window }); },
          "left-of-fold": function(a) { return !$.rightoffold(a, { threshold: 0, container: window }); }
      });
  
  })(jQuery, window);