一个进度条代码的问题 - 编程论坛

这是一个进素条的代码

程序代码：

<body onLoad="processBar.changeMode()" bgcolor="#000000">
<script>
//document.execCommand("BackgroundImageCache",false,true);

function ProcessBar(){
   this.width = 256;
   this.height = 18;
   this.top = 0;
   this.left = 0;
   this.backImg = "process_back.gif";
   this.foreImg = "process.gif";
   this.backDiv = document.createElement("div");
   this.foreDiv = document.createElement("div");
   this.fontDiv = document.createElement("div");

   this.isMoving = false;
   this.nowLength = 0;
   this.moveInterval = 100;
   this.moveRange = 5;
   this.timer;

   ProcessBar.nowObj = this;

   this.init = function(){
        this.foreDiv.style.backgroundImage = "url(" + this.foreImg + ")";
        this.foreDiv.style.backgroundRepeat = "no-repeat";
        this.foreDiv.style.position = "absolute";
        this.foreDiv.style.width = this.nowLength;
        this.foreDiv.style.height = this.height;
        this.foreDiv.style.top = 0;
        this.foreDiv.style.left = 0;

        this.fontDiv.style.background = "transparent";
        this.fontDiv.style.position = "absolute";
        this.fontDiv.style.width = this.width;
        this.fontDiv.style.height = this.height;
        this.fontDiv.style.top = 2;
        this.fontDiv.style.left = 0;
        this.fontDiv.style.textAlign = "center";
        this.fontDiv.style.fontSize = "13px";
        this.fontDiv.appendChild(document.createTextNode(" "));

        this.backDiv.style.backgroundImage = "url(" + this.backImg + ")";
        this.backDiv.style.backgroundRepeat = "no-repeat";
        this.backDiv.style.position = "absolute";
        this.backDiv.style.width = this.width;
        this.backDiv.style.height = this.height;
        this.backDiv.style.top = this.top;
        this.backDiv.style.left = this.left;

        this.backDiv.appendChild(this.foreDiv);
        this.backDiv.appendChild(this.fontDiv);

        document.body.appendChild(this.backDiv);
   }

   this.changeMode = function(){
        this.isMoving = !this.isMoving;

        if(this.isMoving){
            this.timer = window.setInterval(ProcessBar.nowObj.moving, this.moveInterval);
        }else{
            window.clearInterval(this.timer);
        }
   }

   this.moving = function(){
        ProcessBar.nowObj.nowLength += ProcessBar.nowObj.moveRange;
        ProcessBar.nowObj.foreDiv.style.width = ProcessBar.nowObj.nowLength;

        ProcessBar.nowObj.fontDiv.firstChild.data = Math.ceil((ProcessBar.nowObj.nowLength/ProcessBar.nowObj.width)*100) + "%";

        if(ProcessBar.nowObj.nowLength >= ProcessBar.nowObj.width){
            window.clearInterval(ProcessBar.nowObj.timer);
            ProcessBar.nowObj.fontDiv.firstChild.data = "请稍等...";
            top.location.href="http://www.}
   }


}

var processBar = new ProcessBar();
processBar.width=327
processBar.backImg = "upload/2007415102314868.gif"; processBar.foreImg = "upload/2007415102319734.gif"; processBar.top = 300;
processBar.left = 500;
processBar.init();

</script>

</body>

其中

程序代码：

var processBar = new ProcessBar();
processBar.width=327
processBar.backImg = "upload/2007415102314868.gif"; processBar.foreImg = "upload/2007415102319734.gif"; processBar.top = 300;
processBar.left = 500;
processBar.init();

是定义进度条在页面中的位置 processBar.top = 300;
processBar.left = 500;
是用具体数值来定位的我需要使用百分数进行相对定位请问怎么做到

[ 本帖最后由 bodyguard 于 2010-4-11 22:38 编辑 ]