Mozilla Most CSS Compliant Browser

Wednesday March 8th, 2000

According to, Mozilla is currently "the best CSS browser available."

This doesn't mean that the work is done, however. 110 CSS bugs were found in the November 15 1999 build of Mozilla, compared to the next best CSS implementation (IE5, with 155 bugs). We should see those numbers come down in short order as the Mozilla final release approaches.

#1 Bugzilla these?

by sab39

Wednesday March 8th, 2000 8:21 AM

Note that they were using a milestone from Nov '99 - that must have been M11 or M12? They say they will update frequently, but they don't seem to have done so...

On an unrelated note, I wonder if the people at could be persuaded to confirm whether these bugs still exist in the latest nightlies and if so, file bugzilla bugs on them. They have obviously done a *lot* of research on exactly what Mozilla breaks, and I'm sure the layout team would love to know about all of these issues.


#2 See the n.p.m.layout newsgroup...

by mozineAdmin

Wednesday March 8th, 2000 8:37 AM

it looks like they are filing bugzilla reports against their bugs that don't already have reports.


#9 Re: Bugzilla these?

by KaiRo

Wednesday March 8th, 2000 4:41 PM

from what the owner told in n.p.m.layout it was M11 - but he has downloaded a new nightly this weekend...

#3 severity?

by sdm

Wednesday March 8th, 2000 8:43 AM

I noticed many of the bugs they mentioned are not very severe, while others are. Is there any measure of bad the mozilla bugs are compared to the IE ones?

#4 css not only problem; html bugs too

by caseyperkins

Wednesday March 8th, 2000 10:54 AM

The layout engine still has some bugs with normal HTML 4.0, including the frame attribute and the rules attribute of table tags. I'm going to file a bug on these if I can't find them in Bugzilla.

#5 So does that mean IE is better? :)

by Belzebutt

Wednesday March 8th, 2000 11:36 AM

I remember a while ago MozillaAdmin wrote an article saying that while IE supports more of HTML 4.0 than Netscape, it's actually *worse* to support more of a standard (but not all of it). So I guess Mozilla is getting worse and worse, then it will reach its lowest point as only one guy is left, and suddently it will soar to perfection.

I never really agreed with that reasoning :)

#6 Re: So does that mean IE is better? :)

by knollc

Wednesday March 8th, 2000 12:02 PM

I think the exact point was that it's worse to have more HTML 4.0 support but buggy implementation than to have less support but no buggy implementation.

I really agree with that reasoning.


#7 No, I never said that...

by mozineAdmin

Wednesday March 8th, 2000 12:57 PM

What I said was that it's just as bad to support 90% of the spec as 70%. Neither is adequate, because developers will have to work around the 10% or 30% that isn't implemented. However, if half of that 90% implementation is buggy, and the 70% implementation is not buggy, the 70% implementation is better for the standards process (at least it's not partially implemented *and* broken).

#8 Try this! it's all messed up!

by parallel

Wednesday March 8th, 2000 3:42 PM

I tried to view the with M14 and the CSS positioning is all messed up! Is this becasue of Mozilla or the page's programming?

#10 Looks fine to me

by arnoudb

Wednesday March 8th, 2000 5:05 PM

Hmm, looks fine to me (on latest nightly), except that I'm missing a menu on the right. Anyone else having this problem?

#13 Re: Looks fine to me

by basic

Wednesday March 8th, 2000 7:32 PM

Yep missing a menu on the right on build 200030215. Funny thing is that if I do a Save As with IE5 and then load the saved .htm file with Moz the menu appears again. Go figure...

#16 fine on 2000-03-08-08-M15 linux

by RvR

Thursday March 9th, 2000 2:35 AM

really fine and it renders fast. no problem with the right menu. i like this nightly build a lot !

#11 Re: Try this! it's all messed up!

by Dan6992

Wednesday March 8th, 2000 5:18 PM

I know I had the same problem in M13 even though it displays fine in NN4 and IE5. There isn't any CSS positioning in that page, so I'd guess it's a table layout problem not a CSS problem.

#12 Re: Re: Try this! it's all messed up!

by basic

Wednesday March 8th, 2000 6:44 PM

There are some inline CSS positioning in that page. Can't really compare with NS4 because mozilla gets a slightly different page due to javascript. Moz does get the exact HTML as IE though... or so I thought... It seems that when I do a save as on Nav4, IE5 and Moz I get 3 different html files, go figure...

Will investigate further.


#14 How appropriate...

by SomeSmartAss

Wednesday March 8th, 2000 8:15 PM

...that (out-dated) alpha level software is *less* buggy than a MS Final release software.

Excuse me while I swim through this irony. <splash> <splash> <splash>

#15 Re: How appropriate...

by aengblom

Wednesday March 8th, 2000 10:15 PM

Speak quietly my friend or else someone might note the worst (final realeased) browser.

#17 Re: Re: How appropriate...

by thelem

Thursday March 9th, 2000 11:55 AM

What, you mean Communicator? Nah, its not that bad really. HotJava could be a contendor though.

#18 Re: Re: How appropriate...

by Dan6992

Thursday March 9th, 2000 3:16 PM

Communicator has an excuse!!! It was released in May of 1997, only about 5 months after CSS1 became a recomendation (Dec 1996) and a year before CSS2 became a recomdation (May 1998). IE5 on the other hand was released only about a year ago, that's over two years after CSS1 and a year after CSS2.

#21 Re: Re: Re: How appropriate...

by spacecow

Thursday March 9th, 2000 10:04 PM

Actually, I don't think communicator has an excuse. Personally, I'd like to know what netscape was doing before mozilla. I don't mean to be mean, but obviously not everyone is working on mozilla (ie NGLayout mozilla), because 4.xx versions are getting released with an annoying regularity. Why couldn't somebody have fixed the (slightly) buggy implementations of CSS1 stuff that was obviously screwed up, and could be fixed in a couple months, and stuck that in 4.5 instead of a dorky "What's Related" button?

I'd never insult the mozilla team. I think they're doing excellent. I'm just wondering about the rest of Netscape.

#30 Re: Re: Re: Re: How appropriate...

by Dan6992

Saturday March 11th, 2000 5:26 PM

Actually I agree! I only ment the original Communicator had an excuse. 4.5 and higher should atleast have a repaired version of the original implimentation! I actually remember hearing rumors at one time that Netscape was going to fix some of the style problems in 4.5 (and impliment the hover property) when it was first released. However I guess this was a myth. Either that or Netscape decided to abandon the notion of fixing the old layout engine because Mozilla was making such progress with the new one.

#19 Arithmetic wrong on site

by tialaramex

Thursday March 9th, 2000 6:43 PM

The adding up on RichInStyle is very suspect. Somehow 160 listed bugs in IE are counted as 155, while 109 listed bugs in Mozilla counts for 110. I have left a message on the site about this discrepancy...

I too would like to see up-to-date figures, but I'd also like decent arithmetic.

#20 Mozilla Slays IE by a longshot!

by spacecow

Thursday March 9th, 2000 9:56 PM doesn't know s&^*. They're calling "annoying" bugs the same as full-blown severe f-ups. That's not the best part... the best part is (as SomeSmartAss noticed) the browser with the severe f-ups in CSS is the one that isn't being constantly updated and improved because it's not ready for public consumption. I'd say that the compliance should be on a point scale... 1.0 for full, .5 for buggy/annoying, 0 for screwed up/no support.

Don't give me that pussy crap about "well, some compliance is just as bad as none." This is the WEB, and stuff moves at WEBSPEED. If everyone waited around until all their products were perfect, we'd still be waiting for OS/2. Flaws are a natural part of manufacturing, standards or not (hell, even the standards are flawed... there's big support for media-types but no ability to make an image a border or any postscript-like vector abilities that paged media should have).

#22 If nothing else...

by zontar

Friday March 10th, 2000 5:57 AM

Recent builds are doing CSS inheritance very well, unlike NS4.X... (grumble, grumble)

#23 Re: If nothing else...

by NikoP

Friday March 10th, 2000 10:46 AM

NO! Though positioning and so on is very well, there are really annoying bugs like ignoring the background-color, -image, -position. And this hasn't changed since I had the first milestone - I think M10 or M9. Until this hasn't fixed it can be only 3 css-bugs and the css implemention is still s..!

#24 Not XHTML compliant?

by simifilm

Friday March 10th, 2000 6:56 PM

My homepage is fully XHTML and CSS2 compliant according to the validators on When loaded with mozilla, I only get an empty screen. Does mozilla not support XHTML?

#25 Re: Not XHTML compliant?

by Silverthorn

Friday March 10th, 2000 7:46 PM

Am not an expert, but if I were to guess, I'd probably say it was the CSS2. Remember that Mozilla only partially supports CSS2, and they are not garunteeing that it'll even be in the beta release (even though part of it is likely to be in there).

Shawn =)

#27 Probably not CSS2

by simifilm

Saturday March 11th, 2000 1:03 AM

I don't think that CSS2 is the problem. I only use very basic commands which are also part of CSS1...

Any ideas?

#31 Definitely not CSS2

by basic

Saturday March 11th, 2000 6:43 PM

Moz had trouble with the xhtml (xml?) in M14 (and earlier?), It is fixed in the latest nightly builds.

And does anyone knows if the DOM viewer is working? If not will it come alive again? I bet it will give a good overview of a XUL file.


#29 Re: Not XHTML compliant?

by pmg

Saturday March 11th, 2000 11:15 AM

Works for me!

I'm using a March 4th build of mozilla. (IE early m15).

#26 Border units cannot be percentages...

by bloviate

Friday March 10th, 2000 8:17 PM

last I checked. Of course I haven't touched CSS in 6 months so maybe something's changed.

(Mozilla's "failure" to support border %'s is counted as a "bug"....)

#28 Bug count dropping for Mozilla

by zeevon

Saturday March 11th, 2000 8:37 AM

I checked back today and found that Mozilla now has 104 bugs (6 less than before), while IE5 has climbed to 160 bugs.