475191 - bgcolor="lightred" mysteriously comes out blue (quirks mode color parsing)

Status: RESOLVED INVALID

(Core :: CSS Parsing and Computation, defect)

Description

[Eugen Konkov]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; ru; rv:1.9.0.5) Gecko/2008120122 Firefox/3.0.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; ru; rv:1.9.0.5) Gecko/2008120122 Firefox/3.0.5

if I set color = lightred it displayed as blue

Reproducible: Always

Steps to Reproduce:
<table border=1>
<tr bgcolor='lightred'>
<td> HELLO
</table>
Actual Results:  
display blue

Expected Results:  
display red

Comment 1

[Eugen Konkov]

Attachment: test case

Comment 2

[Daniel.S]

I see this as well, but I'm sure it's a bug in our graphic drivers (there are some with red/blue issues), because the color is blue in Fx, IE and Safari (Opera is black).

Please try wether this happens for you in other browsers (Internet Explorer, Opera or whatever you got installed) as well.

Comment 3

[Jesse Ruderman]

I guess Firefox is treating the letters in "lightred" as hex, and somehow it comes out as equivalent to #0000ed despite the extra letters.

If you use a standards-mode doctype, Firefox won't try to do that, and will simply ignore the invalid bgcolor ;)

Comment 4

[Jesse Ruderman]

The comments at http://nedbatchelder.com/blog/200701/color_parsing_brainteaser.html explain what's going on pretty well: Firefox is happy to accept not only #rgb and #rrggbb but also #rrrgggbbb and #rrrrggggbbbb.

http://mxr.mozilla.org/mozilla-central/ident?i=NS_LooseHexToRGB

I have no idea why, though!  This code pretty much hasn't changed since 1999, and the checkins around that time did not include bug numbers:

http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/gfx/src/nsColor.cpp

I guess I should be happy that Firefox, IE, and Safari all do the same thing.

Comment 5

[Jesse Ruderman]

HTML5 will probably standardize something, since color parsing with a missing "#" is an important quirk:

<Hixie> the idea is for the spec to be a complete description of how to implement a user agent (web browser, command line tool, search engine, whatever) in a manner that is compatible with existing content
<Hixie> so that no implementor ever feels the need to do anything not in the spec for compatibility

http://simon.html5.org/specs/html-color-attributes
http://simon.html5.org/test/html/rendering/color-attributes/

I don't think it's worth changing anything until that spec materializes.

Comment 6

[DA]

If you really want 'lightred' to work as a color name you could just include it in the list of color names that firefox recognizes. Just specify an RGB value for light red and stick it in the list.

http://mxr.mozilla.org/mozilla-central/source/gfx/public/nsColorNameList.h

Comment 7

[Bum]

It seems that Firefox is taking the string 'lightred' and treating it as a loose hex. So basically, it's not only light red that does this but also if you put other strings like 'lightaxb' which would still give you a color. So if you want to change the way Firefox handles the parsing of the color, you can modify the nsAttrValue.cpp file, where you can easily change it so it would ignore incorrect colors.

http://mxr.mozilla.org/mozilla-central/source/content/base/src/nsAttrValue.cpp

Comment 8

[Henri Sivonen (:hsivonen) (temporarily away from Bugzilla)]

Confirming, but not an HTML parser bug.

Comment 9

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

lightred isn't a color name defined by any specification as far as I can tell.

Comment 10

[Nochum Sossonko [:Natch]]

I wouldn't say INVALID.

data:text/html,<table border=1><tr bgcolor='lightred'><td> HELLO</table>

this makes a blue bg

data:text/html,<table border=1><tr bgcolor='lightgreen'><td> HELLO</table>

makes a light green bg

data:text/html,<table border=1><tr bgcolor='lightblue'><td> HELLO</table>

makes a light blue bg

Some don't work (eg lightbrown). But the common denominator of all values that don't work is that the bg is black. Why should "lightred" produce a dark blue bg?

PS FYI "lightblack" also produces a dark blue, a slightly darker shade than "lightred" does.

Comment 11

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

The complete list of light-* colors is listed in CSS3COLOR <http://www.w3.org/TR/css3-color/>: lightcoral, lightcyan, lightgoldenrodyellow, lightgray, lightgreen, lightgrey, lightpink, lightsalmon, lightseagreen, lightskyblue, lightslategray, lightslategrey, lightsteelblue and lightyellow. Supporting any others is a bug. If you want to add lightred to that list, you can suggest it on <[e-mail]>.

Comment 12

[Daniel Holbert [:dholbert]]

(In reply to comment #10)
> Some don't work (eg lightbrown). But the common denominator of all values that
> don't work is that the bg is black.
[SNIP]
> PS FYI "lightblack" also produces a dark blue, a slightly darker shade than
> "lightred" does.

See comment 7 for an explanation of why the invalid color names end up producing the color values you observed.

Comment 13

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

This is probably a duplicate, but I wouldn't call it invalid.  We *are* doing something with that color, and the thing in question that we're doing is unexpected.

Comment 14

[j.j.]

With bug 121738 fixed "lightred" stays blue and matches IE and WebKit.

-> INVALID per HTML5 spec and browser compatibility.