How to detect the stock Android browser

var navU = navigator.userAgent;

// Android Mobile
var isAndroidMobile = navU.indexOf('Android') > -1 && navU.indexOf('Mozilla/5.0') > -1 && navU.indexOf('AppleWebKit') > -1;

// Apple webkit
var regExAppleWebKit = new RegExp(/AppleWebKit\/([\d.]+)/);
var resultAppleWebKitRegEx = regExAppleWebKit.exec(navU);
var appleWebKitVersion = (resultAppleWebKitRegEx === null ? null : parseFloat(regExAppleWebKit.exec(navU)[1]));

// Chrome
var regExChrome = new RegExp(/Chrome\/([\d.]+)/);
var resultChromeRegEx = regExChrome.exec(navU);
var chromeVersion = (resultChromeRegEx === null ? null : parseFloat(regExChrome.exec(navU)[1]));

// Native Android Browser
var isAndroidBrowser = isAndroidMobile && (appleWebKitVersion !== null && appleWebKitVersion < 537) || (chromeVersion !== null && chromeVersion < 37);