A simple form:
<?php
require 'HTML/QuickForm.php';

$form = new HTML_QuickForm();
$form->addElement('text','my_name','Your name: ');
$form->addElement('submit','send','Say Hello');

if (
$form->validate()) {
    
$form->process('say_hello');
} else {
    
$form->display();
}

function 
say_hello($data) {
    print 
'Hello, ' $data['my_name'];
}
?>
Output