Would like to modify the DOM entries for a page.

[NaGaZaKi]

I open a page using Javascript (sponsor), it is automatically closed 3mn later but there's an onUnload tag which launches lots of popup's (of course this page is not hosted on my server, I cannot modify it but can perhaps modify the DOM in the browser after it has loaded). As I want my site to be a user friendly site, I don't want these popup's. I'm then looking for a way of deleting the onUnload entry in this page's DOM. I made lots of searches on the net but don't find anything interesting.

Have an idea ? (PHP, Javascript, all UNIX scripting = ok)