[whatwg] Why do we need Mozilla in userAgent string?

Oliver Hunt oliver at apple.com
Sat Mar 26 11:43:14 PDT 2011

Because there are a huge number of sites out there that check for the existence of a feature by doing 'navigator.userAgent.indexOf("mozilla") != -1' or similar (or they decide that the absence of the mozilla term means that you're IE6), so not including the word "mozilla" in the user agent would cause those sites to break.

The majority of the content in modern user agent strings is not about telling the server or client anything useful about the browser, it's about making badly written websites work correctly.


On Mar 26, 2011, at 10:47 AM, Biju wrote:

> Nearly all browsers have word "Mozilla" in userAgent string, hence no
> benefit in detecting that at server.
> So why do we need "Mozilla" in userAgent string?
> Cheers
> Biju

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