js如何判断当前运行环境是ios webview还是android webview

var os = this.os = {}, browser = this.browser = {},
webkit = ua.match(/Web[kK]it[\/]{0,1}([\d.]+)/),
android = ua.match(/(Android);?[\s\/]+([\d.]+)?/),
osx = !!ua.match(/\(Macintosh\; Intel /),
ipad = ua.match(/(iPad).*OS\s([\d_]+)/),
ipod = ua.match(/(iPod)(.*OS\s([\d_]+))?/),
iphone = !ipad && ua.match(/(iPhone\sOS)\s([\d_]+)/),
webos = ua.match(/(webOS|hpwOS)[\s\/]([\d.]+)/),
win = /Win\d{2}|Windows/.test(platform),
wp = ua.match(/Windows Phone ([\d.]+)/),
touchpad = webos && ua.match(/TouchPad/),
kindle = ua.match(/Kindle\/([\d.]+)/),
silk = ua.match(/Silk\/([\d._]+)/),
blackberry = ua.match(/(BlackBerry).*Version\/([\d.]+)/),
bb10 = ua.match(/(BB10).*Version\/([\d.]+)/),
rimtabletos = ua.match(/(RIM\sTablet\sOS)\s([\d.]+)/),
playbook = ua.match(/PlayBook/),
chrome = ua.match(/Chrome\/([\d.]+)/) || ua.match(/CriOS\/([\d.]+)/),
firefox = ua.match(/Firefox\/([\d.]+)/),
firefoxos = ua.match(/\((?:Mobile|Tablet); rv:([\d.]+)\).*Firefox\/[\d.]+/),
ie = ua.match(/MSIE\s([\d.]+)/) || ua.match(/Trident\/[\d](?=[^\?]+).*rv:([0-9.].)/),
webview = !chrome && ua.match(/(iPhone|iPod|iPad).*AppleWebKit(?!.*Safari)/),
safari = webview || ua.match(/Version\/([\d.]+)([^S](Safari)|[^M]*(Mobile)[^S]*(Safari))/)