<html><body>// Variable to check$url = "../index.html";// Validate urlif (!filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED) === false) { echo("$url is a valid URL with a query string");} else { echo("$url is not a valid URL with a query string");}</body><!-- Mirrored from www.w3schools.com/php/phptryit.asp?filename=tryphp_filter_adv3 by HTTrack Website Copier/3.x [XR&CO'2014], Mon, 27 Jan 2020 02:50:47 GMT --></html>