Generating A Conscutive Unique ID

I need a script that will generate a unique ID consecutive to the previous one when a user submits a form. For example, I submit the form and the confirmation page shows:

JGH100354101

I will need the next user that submits the form to have the confirmation page show:

JGH100354102

and so on and so on...

Is anyone aware of a simple form script that would accomplish this?

Seems simple enough, but why do you want to use client-side JavaScript to do this? This is something that should be done with a server-side language.