Thanks to a patch from Scott MacVicar that I've just applied to CVS, PHP 5.2 will have support for httpOnly cookie flag. This neat little feature allows you to mark a newly created cookie as HTTP only, another words inaccessible to browser based scripting languages such as JavaScript. This means it would become far more difficult, if not impossible to steal a user's cookie based session by injecting JavaScript into a page and then using to read cookies.

Definitely a most excellent development! He includes some code examples to show how it will be used, as a seventh parameter to the setcookie/setrawcookie functions (TRUE/FALSE). You can also use an ini_set to make the session cookie behave the same way.

Oh, and PHP4 and 5.1 users can do the same thing of thing, just not as elegantly, with a header call to Set-Cookie manually.