What is cross site scripting?

[webmaster.kwd]

I wanted to know how cross site scripting works.
what are its hazards?
and How to resolve it?

[ralph.m]

It's best to Google questions like this, to save us all typing what's already been typed.

http://en.wikipedia.org/wiki/Cross-site_scripting

Feel free to ask follow-up questions once you've done your initial research.