javascript图片加载完成前显示loading图片-布布扣-bubuko.com

<html>
<title>图片预加载</title>
<body>
<script>
//判断浏览器
var Browser=new Object();
Browser.userAgent=window.navigator.userAgent.toLowerCase();
Browser.ie=/msie/.test(Browser.userAgent);
Browser.Moz=/gecko/.test(Browser.userAgent);

//判断是否加载完成
function Imagess(url,imgid,callback){  
  var val=url;
  var img=new Image();
  if(Browser.ie){
    img.onreadystatechange =function(){ 
      if(img.readyState=="complete"||img.readyState=="loaded"){
        callback(img,imgid);
      }
    }    
  }else if(Browser.Moz){
    img.onload=function(){
      if(img.complete==true){
        callback(img,imgid);
      }
    }    
  }  
  //如果因为网络或图片的原因发生异常，则显示该图片
  img.onerror=function(){img.src=‘http://www.baidu.com/img/baidu_logo.gif‘}
  img.src=val;
}

//显示图片
function checkimg(obj,imgid){
document.getElementById(imgid).src=obj.src;
}
//初始化需要显示的图片，并且指定显示的位置
window.onload=function(){
  Imagess("http://blog.moonsbird.com/wp-content/uploads/2017/04/cropped-82772650889143.58dc29485ed59.jpg","img1",checkimg);
  Imagess("http://blog.moonsbird.com/wp-content/uploads/2017/04/cropped-82772650889143.58dc29485ed59.jpg","img2",checkimg);
  Imagess("http://blog.moonsbird.com/wp-content/uploads/2017/04/cropped-82772650889143.58dc29485ed59.jpg","img3",checkimg);
  Imagess("http://blog.moonsbird.com/wp-content/uploads/2017/04/cropped-8277.jpg","img4",checkimg);
  Imagess("http://blog.moonsbird.com/wp-content/uploads/2017/04/cropped-82772650889143.58dc294","img5",checkimg);
}
</script>
<img id="img1" src="loading.gif" width="100" height="100" />
<img id="img2" src="loading.gif" width="100" height="100" />
<img id="img3" src="loading.gif" width="100" height="100" />
<img id="img4" src="loading.gif" width="100" height="100" />
<img id="img5" src="loading.gif" width="100" height="100" />
</body>
</html>