This can't be done in the way you want it done. Only the user (or more correctly, the user-agent such as Mozilla or IE) can stop the loading of the current page.

While it may be possible that M$ has some sort of ASP or ASP-like extension that will seize control of IE to do something like this, that solution would be specific to M$, and not generally applicable.

You may be better served by having the CGI application responsible for generating the whole page itself, and use one of the many templating engines to express and maintain the HTML part of the display.

--rjray