Detect when mouse leaves window top once and do something

on-exit-window-top.js

var done = false;

function addEvent(obj, evt, fn) {
  if (obj.addEventListener) {
      obj.addEventListener(evt, fn, false);
  }
  else if (obj.attachEvent) {
      obj.attachEvent("on" + evt, fn);
  }
}

addEvent(document, "mouseout", function(e) {
  e = e ? e : window.event;
  var from = e.relatedTarget || e.toElement;
  if ( ( !from || from.nodeName == "HTML" ) && e.clientY <= 1 ) {
    if ( done === false ) {
      done = true;
      console.log('done');
    }
  }
});