var userAgent = navigator.userAgent.toLowerCase();  
var browser = {  
	version: (userAgent.match( /.+(?:rv|it|ra|ie)[\/: ]([\d.]+)/ ) || [])[1],  
	safari: /webkit/.test( userAgent ),  
	opera: /opera/.test( userAgent ),  
	msie: /msie/.test( userAgent ) && !/opera/.test( userAgent ),  
	mozilla: /mozilla/.test( userAgent ) && !/(compatible|webkit)/.test( userAgent )  
};