获取浏览器类型、版本、内核及平台系统

var engine = {
  ie: 0,
  gecko: 0,
  webkit: 0,
  khtml: 0,
  opera: 0,
  ver: null
}
var browser = {
  ie: 0,
  firefox: 0,
  safari: 0,
  konq: 0,
  opera: 0,
  chrome: 0,
  ver: null
}
var system = {
  win: false,
  mac: false,
  x11: false,
  iphone: false,
  ipod: false,
  ipad: fales,
  ios: false,
  android: false,
  nokiaN: false,
  winMobile: false,
  wii: false,
  ps: false
}
var p = navigator.platform
var ua = navigator.userAgent
system.win = p.indexOf("Win") == 0
system.mac = p.indexOf("Mac") == 0
system.x11 = p.indexOf("X11") == 0 || p.indexOf("Linux") == 0
system.iphone = ua.indexOf("iPhone") > -1
system.ipod = ua.indexOf("iPod") > -1
system.ipad = ua.indexOf("iPad") > -1
system.nokiaN = ua.indexOf("NokiaN") > -1

if (system.mac && ua.indexOf("Moblie") > -1) {
  if (/CPU (?:iPhone )?OS (\d+_\d+)/.test(ua)) {
    system.ios = parseFloat(RegExp.$1.replace("_", "."))
  } else {
    system.ios = 2
  }
}
if (/Android (\d+\.\d+)/.test(ua)) {
  system.android = parseFloat(RegExp.$1)
}
if (system.win == "CE") {
  system.winMobile = system.win
} else if (system.win == "Ph") {
  if (/Windows Phone OS (\d+.\d+)/.test(ua)) {
    system.win = "Phone"
    system.winMobile = parseFloat(RegExp["$1"])
  }
}

system.wii = ua.indexOf("Wii") > -1
system.ps = /playstation/i.test(ua)

if (window.opera) {
  engine.ver = browser.ver = window.opera.version()
  engine.opera = browser.opera = parseFloat(engine.ver)
} else if (/AppleWebKit\/(\S+)/.test(ua)){
  engine.ver = RegExp["$1"]
  engine.webkit = parseFloat(engine.ver)
  // 确定是Chrome 还是Safari
  if(/Chrome\/(\S+)/.test(ua)){
    browser.ver = RegExp["$1"]
    browser.safari = parseFloat(browser.ver)
  } else if(/Version\/(\S+)/.test(ua)) {
    browser.ver = RegExp["$1"]
    browser.safari = parseFloat(browser.ver)
  } else {
    var safariVersion = 1
    if(engine.webkit < 100) {
      safariVersion = 1
    } else if(engine.webkit<312) {
      safariVersion = 1.2
    } else if(engine.webkit < 412) {
      safariVersion = 1.3
    } else {
      safariVersion = 2
    }
    browser.safari = browser.ver = safariVersion
  }
} else if(/KHTML\/(\S+)/.test(ua) || /Konqueror\/([^;]+)/.test(ua)){
  engine.ver = browser.ver = RegExp["$1"]
  engine.khtml = browser.konq = parseFloat(engine.ver)
} else if(/rv:\d+[^\)]+\) Gecko\/\d{8}/.test(ua)){
  engine.ver = RegExp["$1"]
  engine.gecko = parseFloat(engine.ver)
  // 确定是不是firefox
  if (/Firefox\/(\S+)/.test(ua)) {
    browser.ver = RegExp["$1"]
    browser.firefox = parseFloat(browser.ver)
  }
} else if(/MSIE ([^;]+)/.test(ua)){
  engine.ver = browser.ver = RegExp["$1"]
  engine.ie = browser.ie = parseFloat(engine.ver)
}