Now and then, when I’m in a big hurry, I use JavaScript’s alert() function to do some quick and dirty debugging. The problem is when one of those happens to be inside a loop that goes through so many iterations that the alerts take control, and you can’t even close the browser window. This script (with the help of Greasemonkey) adds a Cancel button that allows you to temporarily block alerts and get out of that vicious cycle.
Entries from May 2008
Here's the last entry for that month: