gistfile1.js

(function() {
  var focusInHandler = function(e) { e.findElement().fire("focus:in") };
  var focusOutHandler = function(e) { e.findElement().fire("focus:out") };

  if (document.addEventListener) {
    document.observe("focus", focusInHandler, true);
    document.observe("blur", focusOutHandler, true);
  } else {
    document.observe("focusin", focusInHandler);
    document.observe("focusout", focusOutHandler);
  }
})();

document.observe("focus:in", function(e) {
  console.log("focused", e.findElement());
});