It's possible from Javascript without extensions. I did a prototype of this, and while streaming the mouse x&y coords to a server was trivial, the hard part was making sure that what the user is seeing is the same layout I'm seeing myself.
For example if the user has a larger font size, then the layout might be different, so those coordinates would not mean what I think they mean. Faced with this I abandoned my own project on this, but I noticed that sites like http://robotreplay.com/ have appeared, not sure how they dealt with that issue.
For example if the user has a larger font size, then the layout might be different, so those coordinates would not mean what I think they mean. Faced with this I abandoned my own project on this, but I noticed that sites like http://robotreplay.com/ have appeared, not sure how they dealt with that issue.