[Zope] javascript experts?

[Garry Saddington]

I am using some dynamic javascript to build form input controls and I 
have got everything working perfectly in all browsers except IE. The 
javascript uses square bracket notation to allow the 
phones.number:records to build multiple database input records for Zope.

if (eval("document.forms.playlist['phones.number:records'][" + idx + 
"].value") > 0)

However,IE interprets it as:
"document.forms.playlist.phones.number:records"
and of course therefore does not find the element referenced.
Can anyone suggest a workaround for IE in this respect.
Thanks
Garry