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.rel="external nofollow" href="http://support.dmeng.net/upgrade-your-browser.html?referrer="+encodeURIComponent(window.location.href); } @*/ </script>