All popular browsers' user agent strings, even Internet Explorer's, start with Mozilla/. Why is this the case?
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asked Jul 11, 2009 at 17:42
1
It is a long and sad story.
In summary:
- Mozilla browser gets released, with User-Agent
Mozilla/1.0 (Win3.1). It is publicly renamed to Netscape, but in its User-Agent it keeps its original name . - Internet Explorer is released. It spoofs Netscape by starting its User-Agent with
Mozilla/because web servers were routinely browser sniffing and serving pages with frames - a feature supported by both Netscape and IE, but not other browsers of the era - to Netscape only. - Over time, Gecko, Konqueror, Opera, Safari and Chrome each decide to similarly spoof the User-Agent of some previous browser in order to manipulate browser-sniffing web pages into correctly understanding their browser's features. As part of this spoofing, all the browsers start their User-Agents with
Mozilla/, like the browsers before them had done. Plenty of other nonsense also results, like modern Chrome's User-Agent simultaneously claiming to be Mozilla, Chrome, Safari, and 'like Gecko'.
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12 Comments
Note that the "Mozilla" here is not the current open-source project of that name, but the original codename of Netscape, thought to refer to "Mosaic Killer". The codename was reused many years later for the open source project, whose rendering engine is the "Gecko" mentioned here.
And here we are in 2015, still perpetuating the stupidity. MS Edge's user agent string is Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.1.
No wonder it's hard to do browser detection, they're all pretending to be one another!
The browser wars weren't without casualties.
If userAgent String is such a mess, then, why is it not deprecated and/or removed?
I think it had to do with: http://en.wikipedia.org/wiki/User_agent#User_agent_spoofing
Back in the early days, Netscape (code named Mozilla) was the main rival of IE, and they wanted to prevent being rejected by sites rejecting browsers other than Netscape.
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As mentioned by @Jason "Its a long story". Summing that story up "its just every browser pretends to be Mozilla"
After trying everything, I have finally used: http://www.useragentstring.com/
You can use the above website to get the formatted user agent and OS.
They have an API which you can use directly...
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2 Comments
Pedantic correction: every browser, including Mozilla, pretends to be Netscape, whose user-agent began Mozilla. The fact that the codename was reused just adds to the confusion.
Mozilla and Firefox codebase was originally part of Netscape though. That's why many of Firefox internal APIs has "ns" as its prefix.
Reason for this are the infamous browser wars.
In short - browsers started to pretend to be some other browser, because some websites served content based on which browser asked for it and they also wanted content meant for other browsers.
I find it surprising it still haven't been solved to this day. Since userAgent can't be safely removed for legacy reasons, why some new feature clearly identifying a browser wasn't introduced? Yes, most of the time you don't need browser detection, but rather a feature detection, but it is not built-in JS neither!
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Because that's how Netscape identified itself, and Microsoft wanted to work with sites that would detect Netscape and reject anything else.
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Mozilla/5.0 is the general token that says the browser is Mozilla compatible, and is common to almost every browser today. for more detail click here
answered Jul 5, 2017 at 9:49
1 Comment
This is a little misleading - note that the "Mozilla" being referred to is actually the Mozilla (Mosaic-killer) browser, which was rebranded to Netscape before release (and which most readers have probably never heard of by its original name) - not Mozilla the non-profit free software community that's still around today.
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