jquery 页面上所有img加载完毕获取实际宽和高
$(".item img").each(function(){
var $img=$(this);
var realWidth,realHeight;
var img=new Image();
img.src=$img.attr("src");
img.onload=function(){
realWidth=this.width;
realHeight=this.height;
console.log(realWidth+"---"+realHeight);
}
});