来自：https://www.jianshu.com/p/9419df1e3f06
Window内置属性：navigator
//判断设备（苹果，安卓，pc端）
//判断iPhone|iPad|iPod|iOS
if (/(iPhone|iPad|iPod|iOS)/i.test(navigator.userAgent)) {
window.location.href ="iPhone.html";
}
//判断Android
else if (/(Android)/i.test(navigator.userAgent)) {
window.location.href ="Android.html";
}
//判断pc
else {
window.location.href ="pc.html";
};
//正则表达式判断浏览器类型
function userBrowser(){
var browserName=navigator.userAgent.toLowerCase();
if(/msie/i.test(browserName) && !/opera/.test(browserName)){
alert("IE");
return ;
}
else if(/firefox/i.test(browserName)){
alert("Firefox");
return ;
}
else if(/chrome/i.test(browserName) && /webkit/i.test(browserName) && /mozilla/i.test(browserName)){
alert("Chrome");
return ;
}elseif(/opera/i.test(browserName)){
alert("Opera");
return ;
}elseif(/webkit/i.test(browserName) &&!(/chrome/i.test(browserName) && /webkit/i.test(browserName) && /mozilla/i.test(browserName))){
alert("Safari");
return ;
}else{
alert("unKnow");
}
}