Example of a PHP URL and email validation functions

<?php
    // check email
    $email = test_input($_POST["email"]);
    if(!filter_var($email, FILTER_VALIDATE_EMAIL))
    {
        $emailErr = "Invalid email format";
    }
    
    // check URL
    $website = test_input($_POST["website"]);
    if(!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i", $website))
    {
        $websiteErr = "Invalid URL";
    }
?>