对于tom.com首页中的＂免费注册＂gif图片，能不能用javascipt做出那种颜色交换的效果？？

<head>
<script language=javascript>            
<!-- 
function initArray() {
this.length = initArray.arguments.length;
for (var i = 0; i < this.length; i++) {
this[i] = initArray.arguments[i];
    }
}var ctext1 = "欢";
var ctext2 = "迎";
var ctext3 = "光";
var ctext4 = "临";
var speed = 100;
var x = 0;
var color1 = new initArray("blue","red","green","orange");
var color2 = new initArray("green","orange","blue","red");
var color3 = new initArray("red","green","orange","blue");
var color4 = new initArray("orange","blue","red","green");
if (navigator.appVersion.indexOf("MSIE") != -1)
{
document.write('<a href=# ><font id="a">'+ctext1+'</font>');
document.write('<font id="b">'+ctext2+'</font>');
document.write('<font id="c">'+ctext3+'</font>');
document.write('<font id="d">'+ctext4+'</font></a>');
}
function chcolor(mid)
{ 
 if (navigator.appVersion.indexOf("MSIE") != -1)
 {
document.all.a.style.color = color1[x];
document.all.b.style.color = color2[x];
document.all.c.style.color = color3[x];
document.all.d.style.color = color4[x];
 }
(x < color1.length-1) ? x++ : x = 0;
}
setInterval("chcolor()",speed);
-->
</script>
</head>