Question

I’m looking a symbol regex in PHP that will check submitted usernames and reject them if they contain symbols other than an underscore? I want it to also support numbers also.

I have no idea where to start with it… I’ve tried looking online but to no prevail. Thanks in advance. If you could give me a push in the right direction I’d appreciate it hugely.

Answer 1

/^\w+$/

In PHP:

echo preg_match('/^\w+$/',$username);

I encourage you to learn Regular Expressions.

Note: If you weren’t including the underscore, I would suggest ctype_alnum() and avoid Regular Expressions.