<html>
<body>
// Variable to check
$url = "https://www.w3schools.com";
// Remove all illegal characters from a url
$url = filter_var($url, FILTER_SANITIZE_URL);
// Validate url
if (filter_var($url, FILTER_VALIDATE_URL)) {
echo("$url is a valid URL");
} else {
echo("$url is not a valid URL");
}
</body>
</html>