playing a little sound in the background

[eluser]Bramme[/eluser]
Hello everybody

Has anyone ever used Facebooks chat function? When you get a new message, you hear a little beep, warning you someone has said something.

Does anyone know how to recreate something like this? I'm making a website that would need a similar type of functionality: through Ajax I need to check every 5 seconds or so if something has been updated, if it has been, a warning needs to be displayed and a sound played.

Anyone got a clue?