- var_dump: documentation ( source)
- filter_var: documentation ( source)
<?php
var_dump(filter_var('http://www.google.fr', FILTER_VALIDATE_URL));
var_dump(filter_var('www.google.fr', FILTER_VALIDATE_URL));
var_dump(filter_var('https://www.google.fr', FILTER_VALIDATE_URL));
var_dump(filter_var('google.fr', FILTER_VALIDATE_URL));