What would be a good regex to use for validating a username, forbidding all special chars except the "@" symbol in case people want to use their email address as their username?

What would be a good regex to use for validating a username, forbidding all special chars except the "@" symbol in case people want to use their email address as their username?

• javascript

• 3 Just a reminder, you should also validate on the server-side, because a malicious user could bypass your Javascript validation. – muddybruin Commented Feb 15, 2011 at 1:02

2 Answers 2

^([a-zA-Z0-9.]+@){0,1}([a-zA-Z0-9.])+$

This will permit A-Z, a-z, 0-9 and ., and at most one @

Well I guess this may work for your circumstances (see below)...

var userRegex = /^[\w\.@]{6,100}$/;

This will match...

• word characters such as 0-9, A-Z, a-z, _
• literal period
• literal @
• between 6 and 100 characters long

You should probably look at the Email RFC, which states, amongst other characters, that the following are legal: ! # $ % & ' * + - / = ? ^ _ `` { | } ~. This means that the regex above will not allow all emails.

So...

var validUsername = document.getElementById('username').value.match(userRegex);