how to control original htnl file from CGI

[naamabm]

HiI have a page named "index.html".In my main html file I have 2 <iframe>.One of them present a html file while the other is empty.The html is called "top.html" and it is connected to a CGI file (called query.cgi)I need to create a link in "top.html" file (created by query.cgi) that when clicking on it will open a html file on the other iframe.Problem:because "top.html" is created and controlled by "query.cgi" I can't find a way to get the second iframe....parameters I have tried:document.url = undefineddocument.referrer = http://my_server/top.htmlwindow.location.href= http://my_server/query.cgiwindow.document.url = undefinedhow can I reach the main page??