PHP - create seo friendly slug from string

php-generate-seo-slug.php

<?php // credit: http://stackoverflow.com/questions/11330480/strip-php-variable-replace-white-spaces-with-dashes

function seoUrl($string) {
    //Lower case everything
    $string = strtolower($string);
    //Make alphanumeric (removes all other characters)
    $string = preg_replace("/[^a-z0-9_\s-]/", "", $string);
    //Clean up multiple dashes or whitespaces
    $string = preg_replace("/[\s-]+/", " ", $string);
    //Convert whitespaces and underscore to dash
    $string = preg_replace("/[\s_]/", "-", $string);
    return $string;
}