最近研究了京东商城用jQuery的实现如下:
就是默认地址赋给img标签的src2属性,显示时赋给src属性值。
 代码如下:
function lazyload(option) {
 var settings = {
defObj: null,
defHeight: 0
 };
 settings = $.extend(settings, option || {});
 var defHeight = settings.defHeight;
 var defObj = (typeof settings.defObj == "object") ? settings.defObj.find("img") : $(settings.defObj).find("img");
 var pageTop = function() {
return document.documentElement.clientHeight + Math.max(document.documentElement.scrollTop, document.body.scrollTop) - settings.defHeight;
 };
 var imgLoad = function() {
defObj.each(function() {
 if ($(this).offset().top <= pageTop()) {
 var src2 = $(this).attr("src2");
//已显示的不用再显示
if (src2) {
 //显示后,去掉src2属性
 $(this).attr("src", src2).removeAttr("src2");
}
 }
});
 };
 imgLoad();
 $(window).bind("scroll", function() {
 imgLoad();
 });
}
lazyload({
 defObj:".w1"
}); 
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