controlling an instance of a web page from a server....?

[05bit044]

i need to create 2 web pages....one for faculties...and the other for students.Multiple instances of the student page will be accessed at the same time, identified by their login id. Now, i need to create a messaging service( kind of) for the teacher to send messages as a pop up to the student(s) who are currently online.... any idea how this can be implemented....?

or to be short...

can you control an instance of a web page from a server....?

[chazzy]

you can do this using AJAX. i'd suggest that you read up on the approach a bit.