Let's say I accidentally wrote this:

 do { } while (true);

...and then ran it. Apart from killing your browser, is there a way to stop javascript execution (the equivalent of Ctrl+Break in basic, or Ctrl+C)?

Normally, after about 30 seconds your browser asks if you want to stop the long-running script, but this doesn't always happen (as I just found out)!

FYI: A simple loop such as this: for (i=1; i > 0; ++i); will cause my browser to crash (Firefox 3.5b4). I don't feel much like testing to see if it's any of my add-ons. Continuously restarting my browser isn't my idea of a fun Monday night.