Iam using the following code in my file for overlay image.This works fine in firefox but not in IE6.Can anyone please suggest a solution for this??
<div id="1" onclick="document.getElementById('div1').className = 'nodis';" CLASS="nodis" style="width:100%; background:url('/gifs/overlay.png');" align="center">
Png overlays aren't supported in IE6, and you'll have to make use of other hacks* instead.
Or, you could do what Microsoft has already done: drop support for IE6.
Microsoft are pushing out IE8 as a critical security update, so even Windows users that have pirated windows copies will get automatic upgrades from IE6. And large corporations aren't an issue anymore, since very few IT departments in the world want to have unsupported 3rd party software under their responsibility.
If you're still worried that many of your users use IE6, and you want to make sure they can see the page correctly, make use of an update script such as IE6update, which will tell your users that they need a browser update to show your page correctly.
*) Thanks to deceze for the link to various hacks.
I might have misunderstood your question, but here is a solution for PNG fix using javascript: PNGFix. If this is not what you need, please correct me and give me more detailed explanation or link to your site.