[thelist] CSS: colour attributes

Mark Gallagher mark at cyberfuddle.com
Sun Aug 11 12:26:00 CDT 2002


Frank wrote:
 >
 > As far as I understand, colour can be specified in a number of ways
 > in HTML and CSS
 >
 > "white"   a limited number of named colours.
 >
 > "#FFFFFF" hexadecimal, three groups of two.
 >
 > rgb(255,255,255) three groups representing, red, green blue.
 >
 > I've been seeing this "#FFF" all over the place for a long time. At
 > first, I thought that it was simply sloppy code. Then I found Eric
 > Meyer using it. I can't seem to find a reference that details the
 > composition of the statement, even on the w3c. I'm feeling kind'a
 > stumped, kind'a dumb.

As you correctly pointed out, colour can be specified as #FFFFFF
(white), three groups of two.  These three groups are: RRGGBB, or
two-digit hex Red, two-digit hex Green, and two-digit hex Blue.

Where R1 and R2 are equal, G1 and G2 are equal, and B1 and B2 are
equal[0], it's not necessary to specify the second R, G, and B.

So:
#FFFFFF can be written as #FFF, #CCDD33 can be written as #CD3, and so
on - the browser will assume the second digit in each group matches the
first.

Values like #213D94, on the other hand, cannot be shortened.  Nor can
#080008 - *all* groups must contain digits of equal value (within that
group).


[0] Fans of the Australian BC's kids' shows will know that not all B's
     are equal

--
Mark Gallagher
Desperately attempting - and failing - to stay on topic since 1999
fuddleriffic - http://cyberfuddle.com/
blog - http://cyberfuddle.com/infinitebabble/




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