基于jquery的图片懒加载js

以下是实现代码(基于jquery):

function lazyload(option){ 
var settings={ 
defObj:null, 
defHeight:0 
}; 
settings=$.extend(settings,option||{}); 
var defHeight=settings.defHeight,defObj=(typeof settings.defObj=="object")?settings.defObj.find("img"):$(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"); 
if (src2){ 
$(this).attr("src",src2).removeAttr("src2"); 
} 
} 
}); 
}; 
imgLoad(); // 绑定滚动事件 
$(window).bind("scroll",function(){ 
imgLoad(); 
}); 
} 
lazyload({ 
defObj:"#plist" 
})