终端判断

  function detect(ua){
    var os = this.os = {}, browser = this.browser = {},
      webkit = ua.match(/WebKit\/([\d.]+)/),
      android = ua.match(/(Android)\s+([\d.]+)/),
      ipad = ua.match(/(iPad).*OS\s([\d_]+)/),
      iphone = !ipad && ua.match(/(iPhone\sOS)\s([\d_]+)/),
      webos = ua.match(/(webOS|hpwOS)[\s\/]([\d.]+)/),
      touchpad = webos && ua.match(/TouchPad/),
      kindle = ua.match(/Kindle\/([\d.]+)/),
      silk = ua.match(/Silk\/([\d._]+)/),
      blackberry = ua.match(/(BlackBerry).*Version\/([\d.]+)/)

    // todo clean this up with a better OS/browser
    // separation. we need to discern between multiple
    // browsers on android, and decide if kindle fire in
    // silk mode is android or not

    if (browser.webkit = !!webkit) browser.version = webkit[1]

    if (android) os.android = true, os.version = android[2]
    if (iphone) os.ios = os.iphone = true, os.version = iphone[2].replace(/_/g, ‘.‘)
    if (ipad) os.ios = os.ipad = true, os.version = ipad[2].replace(/_/g, ‘.‘)
    if (webos) os.webos = true, os.version = webos[2]
    if (touchpad) os.touchpad = true
    if (blackberry) os.blackberry = true, os.version = blackberry[2]
    if (kindle) os.kindle = true, os.version = kindle[1]
    if (silk) browser.silk = true, browser.version = silk[1]
    if (!silk && os.android && ua.match(/Kindle Fire/)) browser.silk = true
  }