You can also use a UUID (Universally Unique Identifier)
$.rawValue = Uuid(1)
Which results in a string like this:
I've just been playing around with this function recently but the resulting string is rather unwieldy. I like the idea of using Time(), it gives an easier-to-deal-with number as a result - thanks Paul!
I tried it longhand as well and got the same answer... The next problem is getting it to stay static on reopening. I am thinking of getting a convert to string script on the submit button and generating a barcode...