Answer by Chase Seibert for RegEx for Javascript to allow only alphanumeric

Use the word character class. The following is equivalent to a ^[a-zA-Z0-9_]+$:

^\w+$

Explanation:

• ^ start of string
• \w any word character (A-Z, a-z, 0-9, _).
• $ end of string

Use /[^\w]|_/g if you don't want to match the underscore.