jquery实现页面按条件显示图片

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"
})