ie6     =     (parseFloat(navigator.appVersion.split("MSIE")[1]) != 6) ? false : true;
ie7     =     (parseFloat(navigator.appVersion.split("MSIE")[1]) != 7) ? false : true;
ie8     =     (parseFloat(navigator.appVersion.split("MSIE")[1]) != 8) ? false : true;
firefox =     (navigator.userAgent.indexOf("Firefox")==-1) ? false : true;
opera   =     (navigator.userAgent.indexOf("Opera")  ==-1) ? false : true;
chrome  =     (navigator.userAgent.indexOf("Chrome")  ==-1) ? false : true;