又一个小巧的图片预加载类

【 tulaoshi.com - Web开发 】

代码如下：

!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.Length1)
    {
        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;iself.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.LoadedLenself.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;iarr.length;i++)
        {
            str+="img src='"+arr[i]+"' /br";
        }
        document.body.innerHTML+=str;
    });
 //--
 /SCRIPT
/BODY
/HTML