如何实现字幕的淡入淡出效果？？？(javascript)

<script language="javaScript">
<!--
function checkBrowserForVersion4(){
var x=navigator.appVersion;
y=x.substring(0,4);
if(y>=4) Effect();}
var isNav=(navigator.appName.indexOf("Netscape")!=-1);
var colors=new Array
("FFFFFF","FFFFFF","FFFFFF","FFFFFF","FFFFFF","FFFFFF","FFFFFF","F9F9F9","F1F1F1","E9E9E9","E1E1E1","D9D9D9","D1D1D1","C9C9C9","C1C1C1","B9B9B9","B1B1B1","A9A9A9","A1A1A1","999999","919191","898989","818181","797979","717171","696969","616161","595959","515151","494949","414141","393939","313131","292929","212121","191919","111111","090909","000000")
a=0,b=1
function Effect(){
color=colors[a];
//*改改下面的文字内容即可,可使用HTML语法，但是注意引号不要混用。双引号内是单引号。*//
aa="<font size='5'><font face='Arial, Helvetica, sans-serif'><font color="+color+">朋友 !<p>Welcome</font></font></font>"
if(isNav) {document.object1.document.write(aa);document.object1.document.close();}
else object1.innerHTML=aa
a+=b;if (a==38) b-=2;if (a==0) b+=2;xx=setTimeout("Effect()",10);}
//-->
</script>
<body onload="checkBrowserForVersion4()" >
<div id="object1" style="position:absolute; visibility:show; left:181px; top:113px; z-index:2"></div>
<title>
000 </title> 
<p align="center" style="line-height: 20px"> 
<font color="#666666"><span style="font-size: 9pt  
淡入淡出的文字效果
<br> 
</p>                                                       
<hr size="1" noshade width="100%" color="red">                                   
<font face="Arial, Helvetica, sans-serif" color="#666666">                       
<p align="center" style="line-height: 20px"></font>

解决方案 »

  1.   

    我只说原理,
    假设的页面的底色是#FFFFFF,文字的颜色的000000,要做淡出的效果,只需要将文字颜色连续的从FFFFFF变到000000就可以了.
    比如页面的底色是#FFFFFF,文字的颜色是红色ff0000,在256次内将文字显现出来.就将文字颜色变化如下#FFFFFF,#FFEEEE,#FFDDDD,#FFCCCC,.....,#FF1111,#FF0000就可以了
      

  2.   

    用CSS控制透明度
    this.style.filter = "Alpha(Opacity=50)";
      

  3.   

    呵呵 找个例子复制代码
    然后看看
    最后就明白了阿原理就是 用CSS控制透明度 + js控制色彩
    没什么好讲的，就是不怕麻烦，动手去做