Can I Look Up The User Agent From Javascript?

We know it's possible to look up the IP of a visitor using JSON and a callback, as seen here Can I perform a DNS lookup (hostname to IP address) using client-side Javascript? and a

Solution 1:

This string is directly available in navigator.userAgent. However, this string is not very reliable, because the user can easily modify it. Only use it for non-critical purposes.

If you want to detect the user agent, so that you "know" what's supported, you'd better switch to capability-detection.

Examples of alternative methods to detect the browser:

• IE: Conditional comments (HTML (also includes IE version) or in JScript)
• Firefox / Webkit / Opera: Setting a CSS property with a vendor-prefix, and checking for the existence of the just-set property.

Solution 2:

navigator.userAgent contains the user agent string of the browser.