js判断PC端或是移动端

1. 利用了正则表达式和三目运算符，含义就是如果是移动端打开的话那就跳转到 “https:www.baidu.com/”，如果不是就跳转到"http://new.baidu.com/"

window.location.href = /Android|webOS|iPhone|iPod|BlackBerry/i.test(navigator.userAgent) ? "https://www.baidu.com/" :  "http://news.baidu.com/";

等同于

if(/Android|webOS|iPhone|iPod|BlackBerry/i.test(navigator.userAgent)) {
    window.location.href = "https://www.baidu.com/";
} else {
    window.location.href = "http://news.baidu.com/";
}

2.第二种方法

function IsPC() {
    var userAgentInfo = navigator.userAgent;
    var Agents = ["Android", "iPhone",
                "SymbianOS", "Windows Phone",
                "iPad", "iPod"];
    var flag = true;
    for (var v = 0; v < Agents.length; v++) {
        if (userAgentInfo.indexOf(Agents[v]) > 0) {
            flag = false;
            break;
        }
    }
    return flag;
}

3.第三种方法

function browserRedirect() {
    var sUserAgent = navigator.userAgent.toLowerCase();
    var bIsIpad = sUserAgent.match(/ipad/i) == "ipad";
    var bIsIphoneOs = sUserAgent.match(/iphone os/i) == "iphone os";
    var bIsMidp = sUserAgent.match(/midp/i) == "midp";
    var bIsUc7 = sUserAgent.match(/rv:1.2.3.4/i) == "rv:1.2.3.4";
    var bIsUc = sUserAgent.match(/ucweb/i) == "ucweb";
    var bIsAndroid = sUserAgent.match(/android/i) == "android";
    var bIsCE = sUserAgent.match(/windows ce/i) == "windows ce";
    var bIsWM = sUserAgent.match(/windows mobile/i) == "windows mobile";
    if (!(bIsIpad || bIsIphoneOs || bIsMidp || bIsUc7 || bIsUc || bIsAndroid || bIsCE || bIsWM) ){
        window.location.href=B页面;
    }
}
browserRedirect();

4.百度判断的方法

function uaredirect(f) {
 try {
  if (document.getElementById("bdmark") != null) {
   return
  }
  var b = false;
  if (arguments[1]) {
   var e = window.location.host;
   var a = window.location.href;
   if (isSubdomain(arguments[1], e) == 1) {
    f = f + "/#m/" + a;
    b = true
   } else {
    if (isSubdomain(arguments[1], e) == 2) {
     f = f + "/#m/" + a;
     b = true
    } else {
     f = a;
     b = false
    }
   }
  } else {
   b = true
  }
  if (b) {
   var c = window.location.hash;
   if (!c.match("fromapp")) {
    if ((navigator.userAgent.match(/(iPhone|iPod|Android|ios|SymbianOS)/i))) {
     location.replace(f)
    }
   }
  }
 } catch(d) {}
}
function isSubdomain(c, d) {
 this.getdomain = function(f) {
  var e = f.indexOf("://");
  if (e > 0) {
   var h = f.substr(e + 3)
  } else {
   var h = f
  }
  var g = /^www\./;
  if (g.test(h)) {
   h = h.substr(4)
  }
  return h
 };
 if (c == d) {
  return 1
 } else {
  var c = this.getdomain(c);
  var b = this.getdomain(d);
  if (c == b) {
   return 1
  } else {
   c = c.replace(".", "\\.");
   var a = new RegExp("\\." + c + "$");
   if (b.match(a)) {
    return 2
   } else {
    return 0
   }
  }
 }
};

以上是百度总结的