Why is it that Internet Explorer is referred to as 'Mozilla/4.0'? And why is it that Safari, Opera et al. are referred to as 'Mozilla/5.0'?

November 27, 2004 4:46 AM

Why is it that Internet Explorer is referred to as 'Mozilla/4.0'? And why is it that Safari, Opera et al. are referred to as 'Mozilla/5.0'?
posted by tenseone to computers & internet (11 answers total)

http://en.wikipedia.org/wiki/Mozilla has a lot of information on the the term "Mozilla". http://en.wikipedia.org/wiki/User_agent goes into user_agents.

It looks like (if the wikipedia entry on user agents is correct) that Microsoft added "Mozilla" into its user_agent string in order for IE to get content intended for Netscape at the height of the browser wars.
posted by hex1848 at 5:04 AM on November 27, 2004

Thank you for posting the links to Wikipedia. Whenever I follow a link to said site I find myself absorbed for quite a while, following the references and what not.

Though, and I may come across as being completely ignorant (which I am), why is it that the version numbers for Mozilla, as used in the user agent string, are far higher than the current v1.8 build as reported at mozilla.org? ( Even Netscape Navigator v7.x is referred to as Mozilla/5.0. )
posted by tenseone at 5:37 AM on November 27, 2004

I meant to type 'in the opposite direction, even Netscape v7.x...'...
posted by tenseone at 5:42 AM on November 27, 2004

tenseone, I think those 5.0, etc. version numbers are throwbacks to the days when Netscape Navigator was Mozilla.

Marc Andreesen left NCSA [and founded Mosaic Communications, later Netscape Corp] to refine and market a souped-up offshoot of NCSA Mosaic, the early graphical web browser that he developed at NCSA. Originally, "Mozilla" was the internal name for that offshoot.

Years later, Mozilla-the-open-source-browser was initiated to harness the power of thousands of open-source mavens who were looking for something like this to work on [and, as far as I know, didn't have sourceforge or savannah to hang out at yet]. Netscape thought it would give them an edge over Microsoft at a time when IE had finally gained the upper hand in the browser wars.

After a while, Netscape put Navigator 5 on hiatus. The first Netscape browser to use technology from Mozilla-the-open-source-browser was Navigator 6, in much the same manner than Winamp went from 3 to 5. Nonetheless, Mozilla as we know it today is an outgrowth from the never-released Netscape 5, and I think the continued use of Mozilla 5 in the user agent is tribute to that.
posted by britain at 8:50 AM on November 27, 2004

From an innocent bystanders position, my take on that whole thing was that Netscape went through a lot of growing pains post 4.0.

They sorta seemed to bunker down with 4.0 in the hopes that they could just maintain that series then bust out with the next great thing. There were some playing with java and a lot of rendering goodness that forms the basis for what are web standards today, but the next big release was too big to handle and just came at a bad time.

Between IE coming on strong backed by everything MS had and AOL coming in for Netscape, it was probably a very trying time at Netscape. I dunno how they came to the conclusion to open source things, but it was an amazing decision. I can only imagine that Netscape 5.0 was so late to the table and so expensive that they were just looking for anything they could do to get it out.

When I look at user agents, I see Mozilla 4 as meaning "I render what Netscape 4 renders" and when I see Mozilla 5 I read it as "I render what Gecko renders," Gecko being the common rendering engine used by Firefox, Camino, Seamonkey, Galeon, Epiphany, Netscape 6+ and probably other browsers.

As far as versioning, when Netscape released their source, that begat Mozilla which eventually over a couple years released 1.0 of Mozilla, which was also released with some propietary components as Netscape 6. As Mozilla got older, they started Phoenix nee MozillaBrowser nee Firebird nee Firefox which reset the version number again. But all these use Gecko to render.
posted by cmm at 8:52 AM on November 27, 2004

Gosh, thank you so much for taking the time to compose complete, and helpful, answers.

I, too, have become accustomed to thinking of Mozilla/4.0 as 'obsolete' in personal referral reports, and instead investigating Mozilla/5.0 as there is usually myriad browsers to look over ( I have written the code for my referrals to only report the first 8 characters of the user agent string, and therefore I must click one step further to view the string in its entirety ).

Thanks again!
posted by tenseone at 9:47 AM on November 27, 2004

When I look at user agents, I see Mozilla 4 as meaning "I render what Netscape 4 renders" and when I see Mozilla 5 I read it as "I render what Gecko renders," Gecko being the common rendering engine used by Firefox, Camino, Seamonkey, Galeon, Epiphany, Netscape 6+ and probably other browsers.

Don't most of those actually show "Gecko" in the user-agent string? How consistent is that?
posted by gimonca at 10:26 AM on November 27, 2004

They probably all show Gecko in the user-agent string since they use Gecko to render. There's a difference between rending the equivalent of what Gecko would render and actually using Gecko to render.

Put it this way, when MS put Mozilla 4.0 into their user agent for IE, to me they were saying "Dear Web Page: Give us what you'd give Netscape. We can handle it. Honest. Love, Internet Explorer"
posted by cmm at 10:34 AM on November 27, 2004

Dear Web Page: Give us what you'd give Netscape.

Exactly. Which is the same reason that Safari's UserAgent includes "Mozilla/5.0" and Opera's UserAgent includes "Mozilla/4.0".
posted by Danelope at 7:06 PM on November 27, 2004

My only major peeve about Firebird (yes, I need to update) was that it always reported as mozilla 0.7. There are way too many lazy web programmers who's code seems to think that this means I'm running a browser for the early 90s and refuses me access. Always handy.

Am I reading this thread right that they have fixed that with Firefox? Looks like I might need to update...
posted by twine42 at 3:37 AM on November 28, 2004

twine42, my user agent string with Firefox 1.0 is:

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0

So I'd say yes.

Of course, if that doesn't do it for you, you could always use the User Agent Switcher extension to report whatever string you fancy.
posted by catachresoid at 7:04 AM on November 28, 2004