form-validation-example.php

<?php

    if(isset($_POST['submit'])) {

        // Save the values of all of our form data as variables
        $username = $_POST['username'];
        $email = $_POST['email'];
        $message = $_POST['message'];
        
        //Validate $username
        if(!isset($username) || empty($username)) {
            echo "<p>Please fill out your user name.</p>";
        }
        else {
            echo "<p>Username: ".$username."</p>";
        }
        
        //Validate $email
        if(!isset($email) || empty($email)) {
            echo "<p>Please fill out your email.</p>";
        }
        else {
            echo "<p>Email: ".$email."</p>";
        }
        
        //Validate $message
        if(!isset($message) || empty($message)) {
            echo "<p>Please fill out the message field.</p>";
        }
        else {
            echo "<p>Message: ".$message."</p>";
        }
    } else {
      echo "<p>The form was not submitted!</p>";
    }

?>