AutoTab Assistance

I am very new to web developing so this may be a dumb a questions. I have a telephone number area on my page and I want the cursor to move the next field after a person enters the area code, exchange and then finally the number. Can someone please help me with this?

Thanks,

First off, I think this would be bad user interface. It seems nifty in principle, but because people aren't accustomed to such a behavior on the Web, it's more likely to screw them up than to help them. Any time I run across a site that does something like this, I wind up having to back up and re-enter my stuff because I'm accustomed to tabbing through my fields, so I wind up tabbing out of the field I've just been auto-tabbed into.

If you insist, though, look up the onkeypress event (I like devguru.com for this sort of thing) and write a function that for each key press within one of the given text fields does a count of the characters in the field and tabs over if the digit count is correct.