A patch for [Bug 178993] MSIE-extension:HttpOnly cookie attribute for cross-site scripting vulnerability prevention has just been committed to mozilla’s CVS. It is not yet approved for inclusion in 1.8-branch,but trunk will have it since now.
This will help to solve some of XSS-vulnerabilities related problems
update: the patch was removed from tree,for now,but looks like it will be back soon,after passing several bureaucratic procedures

