/*
FF 3.6      - Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.17) Gecko/20110420 Firefox/3.6.17
FF 4.0.1    - Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
FF 5.0      - Mozilla/5.0 (Windows NT 6.1; WOW64; rv:5.0) Gecko/20100101 Firefox/5.0

IE6         - Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1;)
IE7         - Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; SV1;)
IE8         - Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0)
IE9         - Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)]
IE10        - Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; MS-RTC LM 8)

Chrome 11   - Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534.24 (KHTML, like Gecko) Chrome/11.0.696.60 Safari/534.24

Safari 5    - Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.21.1 (KHTML, like Gecko) Version/5.0.5 Safari/533.21.1

Opera 11.11 - Opera/9.80 (Windows NT 6.1; U; en) Presto/2.8.131 Version/11.11
function (is, regex) {
            var m;
            return (is && (m = regex.exec(Ext.userAgent))) ? parseFloat(m[1]) : 0;
        }