浏览器版本低于IE10跳转到指定网页

var userAgent = navigator.userAgent;
var ie6 = (/msies*(d+).d+/g.exec(userAgent.toLowerCase()) || [0, "0"])[1] == "6",
    ie7 = userAgent.indexOf('MSIE 7.0') > -1,
    ie8 = userAgent.indexOf('MSIE 8.0') > -1;
    ie9 = userAgent.indexOf('MSIE 9.0') > -1;
if (ie6 || ie7 || ie8 || ie9){
    window.location.href = 'http://e.jikexueyuan.com/browser.html';
}

极客学院官网copy下来的