1 //JS判断当前设备类型
 2 var os = function (){
 3   var ua = navigator.userAgent,
 4   isWindowsPhone = /(?:Windows Phone)/.test(ua),
 5   isSymbian = /(?:SymbianOS)/.test(ua) || isWindowsPhone,
 6   isAndroid = /(?:Android)/.test(ua),
 7   isFireFox = /(?:Firefox)/.test(ua),
 8   isChrome = /(?:Chrome|CriOS)/.test(ua),
 9   isTablet = /(?:iPad|PlayBook)/.test(ua) || (isAndroid && !/(?:Mobile)/.test(ua)) || (isFireFox && /(?:Tablet)/.test(ua)),
10   isPhone = /(?:iPhone)/.test(ua) && !isTablet,
11   isPc = !isPhone && !isAndroid && !isSymbian;
12   return {
13     isTablet: isTablet,
14     isPhone: isPhone,
15     isAndroid: isAndroid,
16     isPc: isPc
17   };
18 }();
19 if (os.isAndroid || os.isPhone) {
20   alert("phone" ); 
21 } else if (os.isTablet) {
22   alert("pad" );
23 } else if (os.isPc) {
24    alert("pc")
25 }