Understanding User-Agent strings

A User-Agent string is a small piece of text that your Internet browser transmits (each time you visit a web page) that allows the website you are viewing to know what kind of browser you are using. There are lots of different ways in which this information is used by the website, including: gathering of statistics about Internet Browser popularity, tailor the look and feel of the website for the device you are using (e.g. mobile phone), or enable/disable certain features based on the capabilities of your browser, and so on.

There are several ways to find out what the User-Agent string for your browser is (if you’re really that interested):

  1. Enter the following text in your address bar: javascript:alert(navigator.userAgent)
  2. Visit http://www.useragent.org (via Paul Watson)

Microsoft also has a good article that explains them in a little more detail.

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