Cross Site Scripting is the main issue about many web developers today, but it has to do with the Language / Script chooses, well, it is not only about this but also the most secured scripting language does have XSS holes, being an hacker is not a threat because hacking is also part of IT specialization but lets work to prevent XSS holes in the various web that we develop.
If you haven't know anything about XSS, well make research further is the main threat to the global web developers.
If javascript is becoming a threat for web browsers and in IE you need to turn it off, then why javascript so loose to cause havocs, need more enlightens, (Developers Forum, contribute)