his when the document is ready
// this function protects itself against being called more than once
function ready() {
  if (!readyFired) {
      // this must be set to true before we start calling callbacks
      readyFired = true;
      for (var i = 0; i < readyList.length; i++) {
          // if a callback here happens to add new ready handlers,
          // the docReady() function will see that it already fired
          // and will schedule the callback to run right after
          // this event loop f