User agent

The user agent string (AKA UA string) is a string which is visible in the HTTP headers of an HTTP client and in the navigator.userAgent object JavaScript for JS enabled client.

For developer guidance about how to use the user agent string, see:

• https://developer.mozilla.org/en-US/docs/Glossary/User_agent

See: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent

var ua = navigator.userAgent;

• on Firefox OS devices:

User-Agent: Mozilla/5.0 (Mobile; rv:18.0) Gecko/18.0 Firefox/18.0

• MDN: User agent
• Firefox/User Agent
• User Agent Override
• User Agent Detection Libraries