jquery - validate characters on keypress?

Question

I have a form text field that I want to allow only numbers and letters in. (i.e., no #$!, etc...) Is there a way to throw up an error and prevent the keypress from actuall

Answer 1

The above jquery extension (ForceAlphaNumericOnly) is good but still allows the following characters through !@#$%^&*()

On my Mac, when you press the shift key (keycode 16) and then 1, it enters ! but the keycode is 49, the keycode for 1.