<?php
function updateCounter($label)
{
    // Set the label to the current label plus one in a random color.
    $randColor = substr(dechex(rand()), 0, 6);
    $label->set_label('<span color="#' . $randColor . '">' . 
                      ($label->get_text() + 1) .
                      '</span>'
                      );
}

// Create a window to hold the label.
$window = new GtkWindow();

// Set up the window to close cleanly.
$window->connect_simple('destroy', array('Gtk', 'main_quit'));

// Create a label.
$label = new GtkLabel('0');

// Set the label to use markup.
$label->set_use_markup(true);

// Create a button that will be used to increment the counter.
$button = new GtkButton('Click Me!');

// When the button is clicked, the counter should be updated.
$button->connect_simple('clicked', 'updateCounter', $label);

// Create a vbox to hold the label and button.
$vBox = new GtkVBox();

// Add the label & button to the box.
$vBox->pack_start($label);
$vBox->pack_start($button);

// Add the box to the window.
$window->add($vBox);

// Show the window and start the main loop.
$window->show_all();
Gtk::main();
?>