I've never seen a webpage disable the "close tab" button. Are you sure your computer isn't already infected?
for (;;) alert("spam!");
Chrome will, at least, give you an option to disable the alerts if it thinks you're getting them too often, but by that point you're well into scary territory.Footnote: just tried it in Chrome, and after disabling popups I got a tab which was spinning using 100% CPU and which was completely uninteractive. I couldn't even close it using the x on the tab and I had to kill it via the Chrome task manager. Hmmm...
It's hilarious to me that this thing is still a problem when it's technically trivial to solve.
Actually I don't know if the feature was due to vimperator, firefox, or just my window manager.