javascript如何判断是手机还是电脑访问本网页

var system ={};
var p = navigator.platform;
system.win = p.indexOf("Win") == 0;
system.mac = p.indexOf("Mac") == 0;
system.x11 = (p == "X11") || (p.indexOf("Linux") == 0);
if(system.win||system.mac||system.xll){//如果是电脑跳转到百度
window.location.href="http://www.baidu.com/";
}else{ //如果是手机,跳转到谷歌
window.location.href="http://www.google.cn/";
}