javascript判断移动平台

 1 function versions(){
 2         var a = navigator.userAgent;
 3         return navigator.appVersion, {
 4             trident: a.indexOf("Trident") > -1,
 5             presto: a.indexOf("Presto") > -1,
 6             webKit: a.indexOf("AppleWebKit") > -1,
 7             gecko: a.indexOf("Gecko") > -1 && -1 == a.indexOf("KHTML"),
 8             ios: !!a.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/),
 9             android: a.indexOf("Android") > -1 || a.indexOf("Linux") > -1,
10             iPhone: a.indexOf("iPhone") > -1,
11             iPad: a.indexOf("iPad") > -1,
12             webApp: -1 == a.indexOf("Safari")
13 }