As many already posted in other questions (also in jQuery documentation), the old jQuery.browser.version is deprecated and works only in jquery1.3.
Do y
I Found myself having a issue (border radius on frameset with legend) with IE 9 through 11 (did not check IE 12)
MSIE is no long user agent in IE 11 and the appName is Mozilla, however trident is in there
I managed to extract the trident version # and detect it
if(navigator.appVersion.indexOf('Trident/')>-1){// Begin stupid IE crap
var IE=navigator.appVersion;
IE=IE.slice(IE.indexOf('Trident/')+8);
IE=IE.slice(0,IE.indexOf(';'));
IE=Number(IE);
if(IE>=5&&IE<=7) // IE 9 through IE 11
document.body.className='ie';
}