替代jquery中的几个函数

// https://open.alipay.com/developmentAccess/developmentAccess.htm

    var $ = window.jQuery;

    (function() {
      if (!NodeList.prototype.forEach) {
        NodeList.prototype.forEach = function(action) {
          for(var i = 0, l = this.length; i < l; i++) {
            action(this[i]);
          }
        };
      }
      var q = document.querySelectorAll.bind(document);
      var on = function(dom, event, cb) {
        if (!dom) return;
        if ('length' in dom) {
          return dom.forEach(function(elem){
            on(elem, event, cb);
          });
        }
        dom.addEventListener(event, cb);
      };
      var hasClass = function(dom, className) {
        if (!dom) return;
        if ('length' in dom) {
          for(var i = 0, l = dom.length; i < l; i++){
            if (hasClass(dom[i], className)) return true;
          }
          return false;
        }
        if (dom.classList) return dom.classList.contains(className);
        return dom.className.split(' ').indexOf(className) >= 0;
      };
      var addClass = function(dom, className) {
        if (!dom) return;
        if ('length' in dom) {
          return dom.forEach(function(elem){
            addClass(elem, className);
          });
        }
        if (dom.classList) return dom.classList.add(className);
        dom.className += ' ' + className;
      };
      var removeClass = function(dom, className) {
        if (!dom) return;
        if ('length' in dom) {
          return dom.forEach(function(elem){
            removeClass(elem, className);
          });
        }
        if (dom.classList) return dom.classList.remove(className);

        var length = className.length;
        if (dom.className.indexOf(className + ' ') === 0) return dom.className = dom.className.substr(length);
        if (dom.className.indexOf(' ' + className) === dom.className.length - length - 1) return dom.className = dom.className.substr(0, dom.className.length - length - 1);
       
        console.log(dom.className);
        return dom.className = dom.className.replace(' ' + className + ' ', '');
      };
      var parents = function(dom, className) {
        if (!dom) return null;
        var p = dom.parentNode;
        while(p) {
          if (hasClass(p, className)){
            return p;
          }
          p = p.parentNode;
        }
        return p;
      };
      // 点击登录
      on(q('#open-menu-login'), 'click', function(e){
        var curUrl=document.location.href;
        var loginUrl = "https://auth.alipay.com/login/ant_sso_index.htm?goto=" + encodeURIComponent(curUrl);
        window.location.href=loginUrl;
        e.preventDefault();
      });
      //点击退出
      on(q('.logout-link'), 'click', function(e){
        var logoutUrl=encodeURIComponent(document.location.href);
        window.location.href="https://auth.alipay.com/login/logout.htm?goto=" + logoutUrl;
        e.preventDefault();
      });
      // 判断子菜单为当前页面，一级导航高亮显示
      q('.open-submenu-item').forEach(function(item){
        if(hasClass(item, 'selected')){
          var parent = parents(item, 'open-menu-item');
          parent && addClass(parent, 'selected');
          parent && addClass(parent, 'can-disabled-select');
        }
      });
      // 点击搜索出现搜索框
      on(q('#nav-search'), 'click', function(event){
        addClass(q('#open-nav-right-menu'), 'open-search-mode');
        q('#J_SearchKeyword')[0].focus();
      });
      //点击其他区域搜索框消失
      on(q('#nav-search-input'), 'click', function(event){
        event.stopPropagation();
      });
      on(document, 'click', function(){
        removeClass(q('#open-nav-right-menu'), 'open-search-mode');
      });

            window.ENV = (function() {
        var host = window.location.host;
        var env = 'prod';

        if (host.indexOf('.alipay.com') >= 0 && false) {
          env = 'pre';
        } else if (host.indexOf('test.alipay.net') >= 0) {
          env = 'test';
        } else if (host.indexOf('.alipay.net') >= 0) {
          env = 'dev';
        }
        return env;
      })();
    }());