When a URL is submitted from a form input by the user, it is very important to check this URL is valid or not before taking any action on it. Here we’ll provide the simple PHP code to validate a URL in PHP.
Code
$website = $_POST["website"];
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
$message = "Invalid URL";
}