inc/jquery.lazyload-1.9.3.js

   1 /*
   2  * Lazy Load - jQuery plugin for lazy loading images
   3  *
   4  * Copyright (c) 2007-2013 Mika Tuupola
   5  *
   6  * Licensed under the MIT license:
   7  *   http://www.opensource.org/licenses/mit-license.php
   8  *
   9  * Project home:
  10  *   http://www.appelsiini.net/projects/lazyload
  11  *
  12  * Version:  1.9.3
  13  *
  14  */
  15
  16 (function($, window, document, undefined) {
  17     var $window = $(window);
  18
  19     $.fn.lazyload = function(options) {
  20         var elements = this;
  21         var $container;
  22         var settings = {
  23             threshold       : 0,
  24             failure_limit   : 0,
  25             event           : "scroll",
  26             effect          : "show",
  27             container       : window,
  28             data_attribute  : "original",
  29             skip_invisible  : true,
  30             appear          : null,
  31             load            : null,
  32             placeholder     : "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC"
  33         };
  34
  35         function update() {
  36             var counter = 0;
  37
  38             elements.each(function() {
  39                 var $this = $(this);
  40                 if (settings.skip_invisible && !$this.is(":visible")) {
  41                     return;
  42                 }
  43                 if ($.abovethetop(this, settings) ||
  44                     $.leftofbegin(this, settings)) {
  45                         /* Nothing. */
  46                 } else if (!$.belowthefold(this, settings) &&
  47                     !$.rightoffold(this, settings)) {
  48                         $this.trigger("appear");
  49                         /* if we found an image we'll load, reset the counter */
  50                         counter = 0;
  51                 } else {
  52                     if (++counter > settings.failure_limit) {
  53                         return false;
  54                     }
  55                 }
  56             });
  57
  58         }
  59
  60         if(options) {
  61             /* Maintain BC for a couple of versions. */
  62             if (undefined !== options.failurelimit) {
  63                 options.failure_limit = options.failurelimit;
  64                 delete options.failurelimit;
  65             }
  66             if (undefined !== options.effectspeed) {
  67                 options.effect_speed = options.effectspeed;
  68                 delete options.effectspeed;
  69             }
  70
  71             $.extend(settings, options);
  72         }
  73
  74         /* Cache container as jQuery as object. */
  75         $container = (settings.container === undefined ||
  76                       settings.container === window) ? $window : $(settings.container);
  77
  78         /* Fire one scroll event per scroll. Not one scroll event per image. */
  79         if (0 === settings.event.indexOf("scroll")) {
  80             $container.bind(settings.event, function() {
  81                 return update();
  82             });
  83         }
  84
  85         this.each(function() {
  86             var self = this;
  87             var $self = $(self);
  88
  89             self.loaded = false;
  90
  91             /* If no src attribute given use data:uri. */
  92             if ($self.attr("src") === undefined || $self.attr("src") === false) {
  93                 if ($self.is("img")) {
  94                     $self.attr("src", settings.placeholder);
  95                 }
  96             }
  97
  98             /* When appear is triggered load original image. */
  99             $self.one("appear", function() {
 100                 if (!this.loaded) {
 101                     if (settings.appear) {
 102                         var elements_left = elements.length;
 103                         settings.appear.call(self, elements_left, settings);
 104                     }
 105                     $("<img />")
 106                         .bind("load", function() {
 107
 108                             var original = $self.attr("data-" + settings.data_attribute);
 109                             $self.hide();
 110                             if ($self.is("img")) {
 111                                 $self.attr("src", original);
 112                             } else {
 113                                 $self.css("background-image", "url('" + original + "')");
 114                             }
 115                             $self[settings.effect](settings.effect_speed);
 116
 117                             self.loaded = true;
 118
 119                             /* Remove image from array so it is not looped next time. */
 120                             var temp = $.grep(elements, function(element) {
 121                                 return !element.loaded;
 122                             });
 123                             elements = $(temp);
 124
 125                             if (settings.load) {
 126                                 var elements_left = elements.length;
 127                                 settings.load.call(self, elements_left, settings);
 128                             }
 129                         })
 130                         .attr("src", $self.attr("data-" + settings.data_attribute));
 131                 }
 132             });
 133
 134             /* When wanted event is triggered load original image */
 135             /* by triggering appear.                              */
 136             if (0 !== settings.event.indexOf("scroll")) {
 137                 $self.bind(settings.event, function() {
 138                     if (!self.loaded) {
 139                         $self.trigger("appear");
 140                     }
 141                 });
 142             }
 143         });
 144
 145         /* Check if something appears when window is resized. */
 146         $window.bind("resize", function() {
 147             update();
 148         });
 149
 150         /* With IOS5 force loading images when navigating with back button. */
 151         /* Non optimal workaround. */
 152         if ((/(?:iphone|ipod|ipad).*os 5/gi).test(navigator.appVersion)) {
 153             $window.bind("pageshow", function(event) {
 154                 if (event.originalEvent && event.originalEvent.persisted) {
 155                     elements.each(function() {
 156                         $(this).trigger("appear");
 157                     });
 158                 }
 159             });
 160         }
 161
 162         /* Force initial check if images should appear. */
 163         $(document).ready(function() {
 164             update();
 165         });
 166
 167         return this;
 168     };
 169
 170     /* Convenience methods in jQuery namespace.           */
 171     /* Use as  $.belowthefold(element, {threshold : 100, container : window}) */
 172
 173     $.belowthefold = function(element, settings) {
 174         var fold;
 175
 176         if (settings.container === undefined || settings.container === window) {
 177             fold = (window.innerHeight ? window.innerHeight : $window.height()) + $window.scrollTop();
 178         } else {
 179             fold = $(settings.container).offset().top + $(settings.container).height();
 180         }
 181
 182         return fold <= $(element).offset().top - settings.threshold;
 183     };
 184
 185     $.rightoffold = function(element, settings) {
 186         var fold;
 187
 188         if (settings.container === undefined || settings.container === window) {
 189             fold = $window.width() + $window.scrollLeft();
 190         } else {
 191             fold = $(settings.container).offset().left + $(settings.container).width();
 192         }
 193
 194         return fold <= $(element).offset().left - settings.threshold;
 195     };
 196
 197     $.abovethetop = function(element, settings) {
 198         var fold;
 199
 200         if (settings.container === undefined || settings.container === window) {
 201             fold = $window.scrollTop();
 202         } else {
 203             fold = $(settings.container).offset().top;
 204         }
 205
 206         return fold >= $(element).offset().top + settings.threshold  + $(element).height();
 207     };
 208
 209     $.leftofbegin = function(element, settings) {
 210         var fold;
 211
 212         if (settings.container === undefined || settings.container === window) {
 213             fold = $window.scrollLeft();
 214         } else {
 215             fold = $(settings.container).offset().left;
 216         }
 217
 218         return fold >= $(element).offset().left + settings.threshold + $(element).width();
 219     };
 220
 221     $.inviewport = function(element, settings) {
 222          return !$.rightoffold(element, settings) && !$.leftofbegin(element, settings) &&
 223                 !$.belowthefold(element, settings) && !$.abovethetop(element, settings);
 224      };
 225
 226     /* Custom selectors for your convenience.   */
 227     /* Use as $("img:below-the-fold").something() or */
 228     /* $("img").filter(":below-the-fold").something() which is faster */
 229
 230     $.extend($.expr[":"], {
 231         "below-the-fold" : function(a) { return $.belowthefold(a, {threshold : 0}); },
 232         "above-the-top"  : function(a) { return !$.belowthefold(a, {threshold : 0}); },
 233         "right-of-screen": function(a) { return $.rightoffold(a, {threshold : 0}); },
 234         "left-of-screen" : function(a) { return !$.rightoffold(a, {threshold : 0}); },
 235         "in-viewport"    : function(a) { return $.inviewport(a, {threshold : 0}); },
 236         /* Maintain BC for couple of versions. */
 237         "above-the-fold" : function(a) { return !$.belowthefold(a, {threshold : 0}); },
 238         "right-of-fold"  : function(a) { return $.rightoffold(a, {threshold : 0}); },
 239         "left-of-fold"   : function(a) { return !$.rightoffold(a, {threshold : 0}); }
 240     });
 241
 242 })(jQuery, window, document);