[minorgod]

Ah...an easy one. All curly braces in your script must be enclosed in smarty {literal} tags to keep smarty from mistaking the javascript braces as smarty template tags. I usually just enclose the whole script in literal tags unless I need to substitute smarty variables into the actual javascript. So it would look like this in your template.

{literal} 
<SCRIPT language=JavaScript1.2> 
<!-- 
function popup_cvv2_instructions(product_id) { 
     var w = "420"; //width of popup window
     var h = "420"; //height of popup
     window.open('/path/to/cvv2/instructions.html',"cvv2 help window","width="+w+",height="+h+",resizable,scrollbars=yes"); 
} 
--> 
</SCRIPT> 
{/literal} 

Then on your link or button you want to use to open the window, you'd do this:

What's CVV2?

or you could put the exact same syntax from the above href into an onClick event for a button or whatever.