chat engine

so today i came up with a new topic of Chat engines


in that i want to make a chat like never before

So how is that possible ?

It is possible just follow the simple steps


first of i have to make the a proper database in that i have to manage this thing when the user logged in the user_status should change to 1 then the when user logout it should change to 0 .
next when user want to chat with some one means someone so only the user and the second person's
window should popup

so the problem is how this will be done in PHP or javascript