SEO friendly URL. "Löng Strîng" will be converted to > "long-string".

seo-url.php

<?php
	function seoUrl($string, $separator = '-') {
		$accents_regex = '~&([a-z]{1,2})(?:acute|cedil|circ|grave|lig|orn|ring|slash|th|tilde|uml);~i';
		$special_cases = array( '&' => 'and', "'" => '');
		$string = mb_strtolower( trim( $string ), 'UTF-8' );
		$string = str_replace( array_keys($special_cases), array_values( $special_cases), $string );
		$string = preg_replace( $accents_regex, '$1', htmlentities( $string, ENT_QUOTES, 'UTF-8' ) );
		$string = preg_replace("/[^a-z0-9]/u", "$separator", $string);
		$string = preg_replace("/[$separator]+/u", "$separator", $string);
		return $string;
	}