Try to detect features instead of a specific browser. It's more future-proof. Only rarely should you use browser detection.
With that out of the way: one option is to use a library (there are many intricacies to User Agent strings), or alternatively to parse window.navigator.userAgent
manually.
Using a parser library
# https://github.com/faisalman/ua-parser-js.
var parser = new UAParser();
var result = parser.getResult();
var name = result.browser.name;
var version = result.browser.version;
Raw approach with Javascript
# Mozilla/5.0 (Windows NT 10.0) AppleWebKit/537.36 (KHTML, like Gecko)
# Chrome/42.0.2311.135 Safari/537.36 Edge/12.10136
window.navigator.userAgent.indexOf("Edge") > -1
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…