正则表达式验证用户名不起作用

Question

I have this regex:

/^[A-z0-9\._-]{3,24}+$/i

This is supposed to only match a string between 3 and 24 characters long, and only with the characters a-z, A-Z, 0-9, and then also the . _ and - characters.

The problem is this is also matching strings like "^_^". Someone just created a username with exactly that, so this is definitely a problem! Can anyone spot the problem with my regex?

Answer 1

Use this regex:

/^[\w.-]{3,24}$/

A-z is not same as [A-Za-z] as it also includes other characters such as ^ (thanks Jack)

Also remove extra quantifier + after {3,24} which means one or more instances of whole string.

PS: I have also shortened your regex to use \w instead of [A-Za-z0-9_]