Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Why does the useragent include this information? I can't see why a website would need to know.

For example:

Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/534.24 (KHTML, like Gecko) Ubuntu/11.04 Chromium/11.0.696.28 Chrome/11.0.696.28 Safari/534.24

Both Firefox and Chromium on Ubuntu do this.

share|improve this question
I think only linux does this because this is my windows useragent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.204 Safari/534.16 – Ja5087 Apr 2 '11 at 7:23
So the web server knows to serve 64-bit images. Duh. – Apr 2 '11 at 7:40
up vote 5 down vote accepted

This information, when available, is often used by websites to decide which software to recommend you download. If it detects that you have a 64-bit system then it can recommend that you download the 64-bit version of their software.

It is purely down to the useragent (and to some extent the operating system) as to whether it provides this information to the website.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.