Snippet for removing illegal chars from a string.

illegalchars.php

<?php
// Remove illegal chars, replacing them with a dash (-)

$str = "abc är du här? eLLller ELLER kanske däår?";
$str = preg_replace('/[^0-9a-zA-Z]+/', '-', $str);

// results in -> "abc-r-du-h-r-eLLller-ELLER-kanske-d-r-"
echo $str.PHP_EOL;