Strip special characters

[TheBT]

I have a form where the user need to give a new password, but I only want to allow a-z and 0-9 and that's all, so no special characters or even spaces!

How can this be done?

I looked at the strip_tags function:

$pass = strip_tags($pass, '<a><b><i><u>');

But do I need to give all the special characters (like . , ; : # $ & ...)?

Isnt there another function so that this would be easier?

[xblue]

I think you'd be better off with regular expressions, e.g.

// silently replacing all unwanted without notifying the user
// may result in empty strings
$pass = preg_replace('/[^a-z0-9]/', '', $pass);

// or checking for unwanted characters only
// may result in empty strings, too
if (preg_match('/[^a-z0-9]/', $pass){
   echo "invalid";
}

// or checking for wanted characters, which allows specifying a length
if (preg_match('/^[a-z0-9]{4,10}$/', $pass){
   echo "valid";
}

[TheBT]

OK Thanks! 🙂

You guys are great!!!

I hope that one day... I'll be as good as you all! 🆒