Pop ups stop animation

On my web site,  I have a few animated gif's.   I also have links that
pop up in a new window when clicked.

Problem is, the pop up windows stop the animated gifs.

The pop up windows are written in Java script.

Anything I can do to prevent this?   Here's the script I'm using.



<script type="text/javascript">
function openpopup(popurl){
var winpops=window.open(popurl,"","width=540,height=250,left= 40")
}
</script


Any help would be very much appreciated.