用javascript控制图片淡入淡出效果

我测试是好的
<html>
<head>
<meta http-equiv=Content-Type content=text/html; charset=gb2312>
<title></title>
</head>
<body topmargin="0" >
<SCRIPT language=JavaScript1.2>
<!--
var highlighting1,highlighting2,highlighting3;
var thei=0;
//=========1==========
function high(which1,which2,which3){
theobject1=which1;
theobject2=which2;
theobject3=which3;
highlighting1=setInterval("highlightit(theobject1,theobject2,theobject3)",50);

}
function low(which1,which2,which3){
//clearInterval(highlighting)
//which2.filters.alpha.opacity=40
theobject1=which1;
theobject2=which2;
theobject3=which3;
highlighting1=setInterval("lowlightit(theobject1,theobject2,theobject3)",50);
}
function highlightit(cur1,cur2,cur3){
//alert(cur1.filters.alpha.opacity);
if (cur1.filters.alpha.opacity<100)
cur1.filters.alpha.opacity+=10;
if (cur2.filters.alpha.opacity<100)
cur2.filters.alpha.opacity+=10;
if (cur3.filters.alpha.opacity<100)
cur3.filters.alpha.opacity+=10;
else if (window.highlighting1)
clearInterval(highlighting1)
}
function lowlightit(cur1,cur2,cur3){
//alert(cur1.filters.alpha.opacity);
if (cur1.filters.alpha.opacity>40){
cur1.filters.alpha.opacity-=10;
//alert(cur1.filters.alpha.opacity);
}
if (cur2.filters.alpha.opacity>40)
cur2.filters.alpha.opacity-=10;
if (cur3.filters.alpha.opacity>40)
cur3.filters.alpha.opacity-=10;
else if (window.highlighting1)
clearInterval(highlighting1)
}//========&Ouml;÷========
function highorlow(idname1,idname2,idname3){
if (thei==1){
thei=0;
high(idname1,idname2,idname3);
}else{
thei=1;
low(idname1,idname2,idname3);
}
}
var h = setInterval("highorlow(aaa,bbb,ccc);",2000);
//-->
</script><img id="aaa" style="FILTER: alpha(opacity=100);" src="1.jpg" ><br>
<img id="bbb" style="FILTER: alpha(opacity=100);" src="1.jpg" ><br>
<img id="ccc" style="FILTER: alpha(opacity=100);" src="1.jpg" ><br>
</td>
</body>
</html>