Checking for certain chars?

[unknowngiver]

Hey
Can anyone help me do this:

I am trying to check for specific characters in a string..and if they are there...i want it to give an error...i want to check the string "$username" and check for everything that is not a alphanumberical char...

so if it contains ";" or "," or ":" or "}" etc..i want it to give an error
can anyone help me out...

 

[Eric]

<?php

if (preg_match("/([^a-z0-9]+)/i", $string))
{
    die('Error: string can only contain letters (a-z) and numbers (0-9)');
}

?>

 

[nick-8318]

<?php

if (preg_match("/([^a-z0-9]+)/i", $string))
{
    die('Error: string can only contain letters (a-z) and numbers (0-9)');
}

?>

don't you need the ! in !preg_match?

 

[Dan]

No, he did ([^... the ^ means not those characters.