Linux screen-like for Web?

Hello,
Is there something that can help online working with test user from remote place?
I mean package that allows me work on ‘the same’ test webscreen like the other user and exactly what he’s doing on his browser?
If you work on Linux terminal you can do the same idea with screen package to work on one terminal together with more that one person.

… Or have to write something new?.. (& quite hard)