You would have to look into the browser object
The following expression could be used to identify browser version:
Name
Get the name the browser reports for itself. This may be inaccurate for backwards compatibility reasons, e.g. Google Chrome reports its name as Netscape.
Product
Get the product the browser reports for itself. This may be inaccurate for backwards compatibility reasons, e.g. Google Chrome reports its product as Gecko.
UserAgent
Return the full user agent string for the browser, e.g. Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63.
As the manual implies, they can be inaccurate at times, but it's your only way.