jQuery jAM, Season 6

	 
function runLevel(level, Display, andThen) {
var display = new Display(document.body, level);
var running = "yes";
function handleKey(event) {
  if (event.keyCode == 27) {
  if (running == "no") {
 running = "yes";
 runAnimation(animation);
  } else if (running == "pausing") {
running = "yes";
  } else if (running == "yes") {
       running = "pausing";
      }
   }
}
addEventListener("keydown", handleKey);
var arrows = trackKeys(arrowCodes);

function animation(step) {
if (running == "pausing") {
  running = "no";
  return false;
}

level.animate(step, arrows);
display.drawFrame(step);
if (level.isFinished()) {
  display.clear();
//remove all our event handlers
removeEventListener("keydown", handleKey);
arrows.unregister(); // (see change to trackKeys below)
  if (andThen)
   andThen(level.status);
   return false;
     }
  }
  runAnimation(animation);
}

function trackKeys(codes) {
   var pressed = Object.create(null);
   function handler(event) {
     if (codes.hasOwnProperty(event.keyCode)) {
       var state = event.type == "keydown";
       pressed[codes[event.keyCode]] = state;
       event.preventDefault();
     }
   }
addEventListener("keydown", handler);
addEventListener("keyup", handler);

    //new allows runLevel to clean up its handlers
pressed.unregister = function() {
  removeEventListener("keydown", handler);
  removeEventListener("keyup", handler);
 };
    // End of ex 2
    return pressed;
}