如果IE浏览器是IE11以下版本跳转到升级页面

js判断IE浏览器版本，如果版本过低则直接跳转到升级页面 

<script>
      /*@cc_on 
      var temp = window.navigator.userAgent.toUpperCase();
      var charHead = temp.indexOf('MSIE');
      var charLast = temp.indexOf(";", charHead);
      var ieVersion = temp.substring(charHead, charLast);
      ieVersion = ieVersion.split(' ')[1];
      if (ieVersion <= 8) {
          window.location.href="http://support.dmeng.net/upgrade-your-browser.html?referrer="+encodeURIComponent(window.location.href);
      } 
      @*/
    </script>