Back button handler in Cordova Android 4.0.0 app with non-obstructing pedestrian crossing

// Wait for device API libraries to load
//
function onLoad() {
  document.addEventListener("deviceready", onDeviceReady, false);
}

// device APIs are available
//
function onDeviceReady() {
  // Register the event listener
  document.addEventListener("backbutton", onBackKeyDown, false);
}

// Handle the back button
//
function onBackKeyDown(e) {
  e.preventDefault();
  alert("Back button pressed!");
}