WordPress MU

How i enable javascript inside text widgets?

You don't. It's removed because it's a security vulnerability.

There are many thinks that require javascript to work(widgets, adsense...). I now there is a security vulnerability but there are many beneficts to.

You now if there is a way to offer javascript but not php.

A site can be hacked just as easy with javascript as with php.

Is it possible to make it happen? Yes. Would it be responsible to tell someone how to do it? No, it wouldn't. Allowing javascript input by a user is just like opening up full read and write access to your site, or handing the keys over.

There are other ways to achieve the end result, mostly by creating your own widgets.

Or looking to see if the wdiget exists already, like for adsense...

Or write a new one. That's what we do.