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

HTTP

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

Browsers with JavaScript

var ua = navigator.userAgent;

History

• on Firefox OS devices:

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

See Also

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