ExtJS判断IE浏览器类型的方法

ua = navigator.userAgent.toLowerCase(), check = function(r){ return r.test(ua); }, isStrict = document.compatMode == "CSS1Compat", isOpera = check(/opera/), isChrome = check(/chrome/), isWebKit = check(/webkit/), isSafari = !isChrome && check(/safari/), isSafari3 = isSafari && check(/version\/3/), isSafari4 = isSafari && check(/version\/4/), isIE = !isOpera && check(/msie/), isIE7 = isIE && check(/msie 7/), isIE8 = isIE && check(/msie 8/), isGecko = !isWebKit && check(/gecko/), isGecko3 = isGecko && check(/rv:1\.9/), isBorderBox = isIE && !isStrict, isWindows = check(/windows|win32/), isMac = check(/macintosh|mac os x/), isAir = check(/adobeair/), isLinux = check(/linux/), isSecure = /^https/i.test(window.location.protocol);