Question

Given a text input field. How can I prevent users from entering spaces, and other other than letters numbers or dashes (-).

Alphanumerics only – “The alphanumeric character set consists of the numbers 0 to 9 and letters A to Z. In the perl programming language, the underscore character ( _ ) is also considered to be a member of the alphanumeric set of characters”

This is for a field where users can pick a custom url. I would like to prevent users from entering invalid characters.

Ideas? Thanks

Answer 1

You can do this using the jQuery keyup(..) method. You will want to check that the event.keyCode is something valid. If it is not valid, you can prevent the event with preventDefault().

Remember to validate the data sent to the server because anything you do in javascript can be subverted.

Here is a library to do it for you: http://www.itgroup.com.ph/alphanumeric/