又一个小巧的图片预加载类_JavaScript

又一个小巧的图片预加载类

<!doctype html public "-//w3c//dtd xhtml 1.0 transitional//en" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-transitional.dtd"> 
<html> 
<head> 
<title> new document </title> 
<meta http-equiv="content-type" content="text/html; charset=utf-8" /> 
<script language="javascript"> 
<!-- 
var ie=navigator.appname=="microsoft internet explorer"; 
var opera=navigator.appname.tolowercase()=="opera"; 
var ff=!ie && !opera; 
function loadimage(arrsrc,callback) 
{ 
    this.length=arrsrc.length; 
    this.loadedlen=0;    //已经被加载的图片个数 
    var self=this; 
    if(self.length<1) 
    { 
        callback(arrsrc); 
        return; 
    } 

    //经测试,opera与别的浏览器加载方式不同,所以特别独立开来... 
    if(opera) 
    { 
        for(var i=0;i<self.length;i++) 
        { 
            var tmpimg=new image(); 
            tmpimg.src=arrsrc[i]; 
            tmpimg.onload=function() 
            { 
                self.loadedlen++; 
                if(self.loadedlen==self.length && callback)    callback(arrsrc); 
            } 
        } 
        return; 
    } 

    this.load=function() 
    { 
        self.loadedlen++; 
        document.getelementbyid("counter").innerhtml=self.loadedlen; 
        if(self.loadedlen<self.length)    self.downimg(); 
        else if(callback)    callback(arrsrc); 
    } 

    this.downimg=function() 
    { 
        var tmpimg=new image(); 
        tmpimg.src=arrsrc[self.loadedlen]; 
        if(ie) 
        { 
            if(tmpimg.readystate=="complete")    self.load(); 
            else    tmpimg.onreadystatechange=function() 
            { 
                if(this.readystate=="complete")    self.load(); 
            } 
        } 
        else    tmpimg.onload=self.load; 
    } 
    this.downimg(); 
} 
//--> 
</script> 
</head> 
<body> 
<div id="counter"></div> 
 <script language="javascript"> 
 <!-- 
    var arr=['http://photo.hjbbs.com/photo/20060531/20060531103027226_756_o.jpg','http://img1.soufun.com/bbs/2007_02/13/1171345302199.jpeg','http://img.c8c8.cn/2006/09/09/15032/pp20060909002749.jpg']; 
    var t=new loadimage(arr,function(arr) 
    { 

        var str=""; 
        for(var i=0;i<arr.length;i++) 
        { 
            str+="<img src='"+arr[i]+"' /><br>"; 
        } 
        document.body.innerhtml+=str; 
    }); 
 //--> 
 </script> 
</body> 
</html>