[Zope] TAL expressions within Javascipt?

[mclinden at informed.net]

I'm moving an existing web site into Zope because the primary purpose of 
this site is document management and I want to be able to utilize Zope for 
content control. But the existing site has a large number of javascripted 
behaviors that are conditionally enabled based upon such things as browser 
capabilities. In particular, the system is setup to dynamically load 
certain scripts if certain capabilities exist. The form is:

document.write("<scr" + "ipt src='http://x.y.z/custom.js' 
type='text/javascript'><\/scr" + "ipt>");

I would like to be able to change the "custom.js" file on a folder by 
folder basis, i.e.,

<script type="text/javascript" tal:attributes="src 
here/custom.js/absolute_url"></script>

...but can't figure out the appropriate way to do so within Javascript.

Suggestions/pointers would be appreciated.

Sean McLinden
Allegheny County Health Department