Minimalist browser userAgent parsing based on data from https://developer.mozilla.org/en-US/docs/Browser_detection_using_the_user_agent

browser.js

//Minimalist browser name/version parsing based on data from 
//https://developer.mozilla.org/en-US/docs/Browser_detection_using_the_user_agent
function createBrowserRegex(browser){
	return new RegExp('\\b('+browser+')\\/([^\\s]+)');
}
function createBrowserTest(userAgent, positive, negatives){
	var matches = BROWSER_REGEX[positive].exec(userAgent);
	negatives=negatives||[];
	if(matches && matches.length && !negatives.some(function(negative){return BROWSER_REGEX[negative].exec(userAgent)})){
		return matches.slice(1,3);
	}
}
var BROWSER_REGEX=["Seamonkey", "Firefox", "Chromium", "Chrome", "Safari", "Opera"].reduce(function(p,c){
	p[c]=createBrowserRegex(c);
	return p;
},{});
BROWSER_REGEX["MSIE"]=new RegExp(";(MSIE) ([^\\s]+)");
var BROWSER_TESTS=[
	["MSIE"],
	["Opera", []],
	["Seamonkey", []],
	["Firefox", ["Seamonkey"]],
	["Chromium", []],
	["Chrome", ["Chromium"]],
	["Safari", ["Chromium","Chrome"]]
].map(function(arr){
	return createBrowserTest(navigator.userAgent, arr[0], arr[1]);
});

BROWSER_TESTS.reduce(function(p,c){return (c)?c:p;}, "UNKNOWN");