Bruce: All right, anyone else? Hello, how 'bout you, mate? What's your problem?
Marlin: Me? I don't... I don't have a problem.
Bruce: Oh. Okay...
Anchor: Denial.
As web developers, we constantly need to activate the "Script Debugger" in order to make sure everything works fine and to prevent the browser from hiding errors.

Indeed, on average, 1 page on 5 does contain at least one JavaScript related error. You may not see them, but that's because the browser is kind enough to hide developers' mistakes...
Sometimes, it's not so important, but we can't let this kind of errors in a Web Application. It's fun to see that even web-only developpers like Google can leave such stupid mistakes. The most common error? The string constant that contains quotes...

Personally, sometimes, I feel like I'm doomed and sometimes I send those errors to the webmaster.
Track them! Spam their authors! It will lead to a better world ;-)
Enjoy !
Au revoir, à bientot,
Cedric