fastclick中的用户代理判断：
windows Phone
/**
* Windows Phone 8.1 fakes user agent string to look like Android and iPhone.
*
* @type boolean
*/
var deviceIsWindowsPhone = navigator.userAgent
.indexOf("Windows Phone") >= 0;
Android
/**
* Android requires exceptions.
*
* @type boolean
*/
var deviceIsAndroid = navigator.userAgent.indexOf('Android') > 0
&& !deviceIsWindowsPhone;
IOS
/**
* iOS requires exceptions.
*
* @type boolean
*/
var deviceIsIOS = /iP(ad|hone|od)/.test(navigator.userAgent)
&& !deviceIsWindowsPhone;
IOS4
/**
* iOS 4 requires an exception for select elements.
*
* @type boolean
*/
var deviceIsIOS4 = deviceIsIOS
&& (/OS 4_\d(_\d)?/).test(navigator.userAgent);
IOS6~7
/**
* iOS 6.0-7.* requires the target element to be manually derived
*
* @type boolean
*/
var deviceIsIOSWithBadTarget = deviceIsIOS
&& (/OS [6-7]_\d/).test(navigator.userAgent);
黑莓
/**
* BlackBerry requires exceptions.
*
* @type boolean
*/
var deviceIsBlackBerry10 = navigator.userAgent.indexOf('BB10') > 0;
