图片加载完成再执行事件的实例

//图片加载
function load(imgSrc,callback) {
 var imgs = [];
 var c = 0;
 for (var i = 0; i < imgSrc.length; i++) {
  imgs[i] = new Image();
  imgs[i].src = imgSrc[i];
  imgs[i].onload = function(){
   c++
   if(c == imgSrc.length){
    if(callback){
     callback();
    }
   }
  }
 }
 return imgs;
}