Hello,
I guessed following.
Scenario:
I have a page that holds 2 frames - left.htm and content.htm, named accordingly left and contents.
Then from some of link in left.htm in place of content.htm comes yyy.htm for which the left frame needs to be zzz.htm (not original left.htm).
The code:
in file yyy.htm
<body onload="parent.left.location='zzz.htm'">
The event you need is onload.
The way of accessing frames is according DOM (document object model).
Hope this helps.
D.