Przyspieszenie dziaƂania operatora in na vstorage.
[redakcja.git] / platforma / static / js / lib / jquery.lazyload.js
1 (function($) {
2     jQuery.fn.lazyload = function(pattern, options) {
3         var settings = {
4             threshold: 0,
5             scrollThreshold: 300,
6             placeholder: 'loading...',
7             checkInterval: 2000
8         };
9         
10         if (options) {
11             $.extend(settings, options);
12         }
13         
14         var container = this;
15         container.data('lazyload:lastCheckedScrollTop', -10000);
16         
17         function aboveViewport(container, element, threshold) {
18             return $(container).offset().top >= $(element).offset().top + $(element).height() + threshold;
19         }
20         
21         function belowViewport(container, element, threshold) {
22             return $(container).offset().top + $(container).height() + threshold <= $(element).offset().top;
23         }
24         
25         function checkScroll() {
26             if (container.data('lazyload:lastCheckedScrollTop') == undefined) {
27                 return;
28             }
29             if (Math.abs(container.scrollTop() - container.data('lazyload:lastCheckedScrollTop')) > settings.scrollThreshold) {
30                 container.data('lazyload:lastCheckedScrollTop', container.scrollTop());
31                 
32                 $(pattern, container).each(function() {
33                     if (aboveViewport(container, this, settings.threshold)
34                         || belowViewport(container, this, settings.threshold)) {
35                         $(this).html(settings.placeholder);
36                     } else {
37                         $(this).html('');
38                         var self = this;
39                         $('<img src="' + $(this).attr('src') + '" width="' + $(this).width() + '" />').load(function() {
40                             if ($(this).height() > $(self).height()) {
41                                 $(self).height($(this).height());
42                             }
43                         }).appendTo(this);
44                     }
45                 })
46             }
47             setTimeout(checkScroll, settings.checkInterval);
48         }
49         
50         checkScroll();
51     };
52 })(jQuery);