combining 'back to' and get url

[Hammerhed]

Problem: I'm calling pages from other sites into an iframe in my own page and want a 'back' button so that once user has browsed 2 or more pages, user can go back a page. At moment, all I can offer is to reload orginal page into the iframe.
Thought about using a back button, eg:
<FORM>
<INPUT TYPE=&quot;Button&quot; VALUE=&quot;Back&quot;
onClick=&quot;history.go(-1)&quot;>
</FORM>
but, of course, this applies only to my pages, not to the off-site pages being browsed in the iframe. I guess that what's needed is to read the url of the iframe pages and feed that to the back button. Can you pls advice how this might be done?

 

[Hammerhed]

Duh!
Sorry for bothering you with this... the script I posted works fine even with external links within an iframe...
Cheers!