ok, i have this, but its not working..

Code:
<a href="javascript:void(0)" onclick="window.open('URL','Shipping Terms','resizable=yes,scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no')">Shipping Terms</a>
I want to have a script in my header as the reference to pop-ups instead of having to re-type attributes on every page i want a popup, wat would be the code for this, thanks