form-handler.js

// A simple event handler for submitting a form via AJAX,
// then closing its containing window.
function submitForm(element) {
  // This is a Prototype method for submitting a form
  $(element).request({
    // This is a callback that will be invoked once the
    // request finishes. It just closes the window.
    onComplete: function() { window.close(); }
  });

  // Prevent the form from actually submitting and reloading
  // the page:
  return false;
}

// Wait until the page has loaded...
$(document).observe('dom:loaded', function() {
  // ...then unobtrusively assign the event handler. This
  // this prevents the need for the "onclick" attribute in
  // your HTML markup.
  $('contact').observe('submit', submitForm);
});