How can I use AJAX for form validation?

How can I use AJAX for form validation?

You can use AJAX to send form data to the server without reloading the page. This allows for real-time validation.

Can you show me a simple example of how to implement this?

Sure! You can use jQuery to simplify AJAX calls. Here's a basic example:

$('#myForm').on('submit', function(e) {
    e.preventDefault(); // Prevent the default form submission
    $.ajax({
        type: 'POST',
        url: 'validate.php',
        data: $(this).serialize(),
        success: function(response) {
            // Handle the response from the server
            $('#result').html(response);
        }
    });
});

What should the server-side script look like?

The server-side script (e.g., validate.php) should check the submitted data and return a response indicating whether it's valid or not. For example:

if ($_POST['username'] == 'existingUser') {
    echo 'Username already taken.';
} else {
    echo 'Username available!';
}