I have a website which has a mysql db which records how many visitors i have.
I want a message box to pop up everytime a visitor logs on.

Whenever someone logs on, a php file constantly is run (via javascript) checks to see if the visitor counter has increased.
if it does it plays a "ping" sound. this works fine, but I think as the php file is seperate from my index.php
the message never appears.

is there a way to check in javascript that when a responsetext (ajax) changes from the current value being polled that it executes a function? (ie, the notify box)

many thanks.... twisting my melon.... kev