/**  * @function Monitor whether the document tree is loaded.  * @param fn  */ function domReady(fn) {
      if (document.addEventListener) { // 标准浏览器         document.addEventListener('DOMContentLoaded', function () { //注销时间，避免重复触发             document.removeEventListener('DOMContentLoaded', arguments.callee, false);             fn(); // 运行函数         }, false);     } else if (document.attachEvent) { // IE浏览器         document.attachEvent('onreadystatechange', function () {
              if (document.readyState == 'complete') {
                  document.detachEvent('onreadystatechange', arguments.callee);                 fn(); // 函数运行             }         });     } }

domReady(loadStart);