You may need to quickly switch between user-agent strings on the fly - when developing websites that need to work on both mobile browsers and desktop browsers user-agent switcing is a must-have. And some times you’ll expirence some archaic site blocking you because you’re not using Netscape or Internet Explorer (in an ancient version e.g. version 6). Chrome got a built-in user-agent switcher. All you need to do is to open the developer tools panel (use Ctrl+Shift+I shortcut) and click the wrench button (lower right corner) and click Overrides, and enable override user agent and elect the browser or device you want to emulate and reload the page.