Detecting when an iframe gets or loses focus

Question

What\'s the correct way of detecting when an iframe gets or loses focus (i.e. will or will not receive keyboard events)? The following is not working in Fx4:

Answer 1

This might work

document.addEventListener('click', function(event) {
  var frame= document.getElementById("yourFrameID");

  var isClickInsideFrame = frame.contains(event.target);

  if (!isClickInsideFrame ) {
    //exec code
  }

});