check frame url and link

The situation is like this. I have like a email site ( http://mail.jalvemo.com ) that’s log in to a mail server (I can’t change the mail server script. I can only make @jalvemo users and log in to the server through my site.)
if you fail to log in on my Email-login site, you get linked to the "failed to log in site"(the mail servers failed to log in site, not mine).
The same thing happens when you log out from my mail, then you get to the mail servers log in site,

so if I make two frames and open all the sites in a “main frame”, I hoped that an other frame could check if the mail servers sites were open and redirect to my sites..


so can i make a script like this?

If "http://mailserver.com/FailedLogin.htm" is loaded in frame:"_myframe"
--->
open url: "http://mail.jalvemo.com/failed.htm" in frame:"_myframe"

how to do that? Or do you have a other solution?
Please answer in English (or Swedish)