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;