javascript如何判断是手机还是电脑访问本网页

 1  var system ={};  
 2     var p = navigator.platform;       
 3     system.win = p.indexOf("Win") == 0;  
 4     system.mac = p.indexOf("Mac") == 0;  
 5     system.x11 = (p == "X11") || (p.indexOf("Linux") == 0);     
 6     if(system.win||system.mac||system.xll){//如果是电脑跳转到百度  
 7         window.location.href="http://www.baidu.com/";  
 8     }else{  //如果是手机,跳转到谷歌
 9         window.location.href="http://www.google.cn/";  
10     }