validate numbers?

[ryanc]

How do you validate numbers entered into a form? For example say I had a text area in my form for a phone number and the user enters letters instead of numbers in the text area and I want to alert them only use numbers. How would I do this? Any help would be greatly appreciated.

Thanks,
ryanc

[CaseyRyan]

Here's an example [javascript.internet.com] of a very useful script which you can use to validate phone numbers, zip codes, etc.

-=casey=-

[rocknbil]

if (isNaN(your_number_variable)) { alert('Numbers only'); }
NaN = Not a Number

[SpaceFrog]

regExp is a magic word ... ;-)