In many browsers you can do something like this:
javascript: alert("...");
Is there any way to combine that with a url? I'm thinking of something like this:
http://example.com?javascript: alert("...");
The effect would be that the javascript would be executed after the page is loaded (same effect as loading the URL and then entering the above javascript statement)
Edit: I can't use window.onload or anything like that because I don't necessarily own the page.