// Attach handler to window load event
Event.observe(window, 'load', init, false);

function init() {
  // Attach handler to form's submit event
  Event.observe('emailForm', 'image', storeAddress);
}

function storeAddress(e) {
  // Update user interface
  $('response').innerHTML = 'Adding email address...';
  // Prepare query string and send AJAX request
  var pars = 'email=' + escape($F('email'));
  var myAjax = new Ajax.Updater('response', 'ajax.php', {method: 'get', parameters: pars});
  // Stop form from submitting when JavaScript is enabled
  Event.stop(e);
}