代码在ext里的src\core\ext.js下
最新的ext3.0beat1的代码如下：
复制代码 代码如下:
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);
而2.2.1下（在source\core\ext.js里）的为
复制代码 代码如下:
var ua = navigator.useragent.tolowercase();
var isstrict = document.compatmode == css1compat,
isopera = ua.indexof(opera) > -1,
ischrome = ua.indexof(chrome) > -1,
issafari = !ischrome && (/webkit|khtml/).test(ua),
issafari3 = issafari && ua.indexof('webkit/5') != -1,
isie = !isopera && ua.indexof(msie) > -1,
isie7 = !isopera && ua.indexof(msie 7) > -1,
isie8 = !isopera && ua.indexof(msie 8) > -1,
isgecko = !issafari && !ischrome && ua.indexof(gecko) > -1,
isgecko3 = isgecko && ua.indexof(rv:1.9) > -1,
isborderbox = isie && !isstrict,
iswindows = (ua.indexof(windows) != -1 || ua.indexof(win32) != -1),
ismac = (ua.indexof(macintosh) != -1 || ua.indexof(mac os x) != -1),
isair = (ua.indexof(adobeair) != -1),
islinux = (ua.indexof(linux) != -1),
issecure = window.location.href.tolowercase().indexof(https) === 0;