alert beep sound new user comes

hello...

i am doing private chat concept.i am doing this using php,mysql. wamp server. i want to alert beep sound when new user comes in. how to do? i am displaying every thing when new user comes in user details will comes at admin side. but at the same i want to alert beep sound when new user comes.

Uh... this isn't a PHP question, as PHP doesn't do anything on the user end.

As you're doing a chat system (which is what I assume you mean), you have Javascript running, that's the only way to run a sound clip.