使用js实现文字发光效果

<span id="theText" style="width:100%">
<h2>JavaScript</h2>
</span>
<script language="javascript">
<!--
var from = 5;            
var to = 11;             
var delay = 55;          
var CColor = "#fc4919";
var i = to;
var j = 0;
textDown();
function textUp()
{
if (!document.all)       
return
if (i < to)
{
 theText.style.filter = "Glow(Color=" + CColor + ", Strength=" + i + ")";
 i++;
 setTimeout('textUp()',delay);            
 return;
}
if (i = to)
{
setTimeout('textDown()',delay);          
return;
}
}

function textDown()
{
if (!document.all)
return
if (i > from)
{
theText.style.filter = "Glow(Color=" + CColor + ", Strength=" + i + ")";
i--;
setTimeout('textDown()',delay);           
return;
}
if (i = from)
{
setTimeout('textUp()',delay);             
return;
}
}
//-->
</script>