I'm building a shopping cart and I would like to use a JavaScript function to validate user input when entering the quantity value in the quantity text input. I would like to allow the entering of integer values only (no floats, no other characters).

I know that I can apply this function using onKeyUp event and also I found isNaN() function, but it returns true even for floats (which is not ok).

Can you guys help me out with this one?

Thanks.

I'm building a shopping cart and I would like to use a JavaScript function to validate user input when entering the quantity value in the quantity text input. I would like to allow the entering of integer values only (no floats, no other characters).

I know that I can apply this function using onKeyUp event and also I found isNaN() function, but it returns true even for floats (which is not ok).

Can you guys help me out with this one?

Thanks.

• javascript

• 1 there is a nice jQuery plugin for this: digitalbush./projects/masked-input-plugin – meo Commented Jun 6, 2010 at 20:11
• Don't forget to validate on the server side, too. It's very easy to stop JavaScript outputting 'irritating' messages like “Hey you! You're supposed to only input numbers here!”. – Marcel Korpel Commented Jun 6, 2010 at 21:03
• @meo, pretty nice indeed. Thanks. – Psyche Commented Jun 6, 2010 at 22:28

1 Answer 1

You can always check with parseInt:

if (number == parseInt(number))