HTML and CSS Reference
In-Depth Information
rgba(rrr
,ggg,bbb,a.aa)
rgba(rrr
gba(rrr,ggg,bbb,a.aa)
.rr%,ggg.gg%,bbb.bb%,a.aa)
hsla(hhh.hh,sss.ss%,lll.ll%,a.aa)
gba(rrr.rr%,ggg.gg%,bbb.bb%,a.aa)
hsla(hhh.hh,sss.ss%,lll.ll%,a.aa)
This extends the previous three formats to include an alpha (opacity) value. The alpha
value must be a real number between
0
and
1
inclusive; percentages are not permitted
for the alpha value. Thus,
rgba(0,0,255,0.5)
and
rgba(0,0,100%,0.5)
and
hsla(0,100%,50%,0.5)
are equivalent half-opaque red. There is no hexadecimal notation
for RGBA.
<keyword>
One of 17 recognized keywords based largely on the original Windows VGA colors. These
keywords are
aqua
,
black
,
blue
,
fuchsia
,
gray
,
green
,
lime
,
maroon
,
navy
,
olive
,
or-
ange
,
purple
,
red
,
silver
,
teal
,
white
, and
yellow
. Browsers generally also recognize
other keywords, such as the 147 X11 color keywords documented in section 4.3 of the
W3C CSS3 Color Module specification (
http://www.w3.org/TR/css3-color
). The CSS3
Color Module drops
orange
from the list of recognized basic keywords, but it appears in
the X11 list and all known browsers support it for historical reasons.
currentColor
A special keyword that represents the current computed value of the element's
color
property. This means that you could declare
background-color: currentColor
and set
the element's background the same color as its foreground (not recommended). When ap-
plied to the
color
property, it is equivalent to declaring
color: inherit
. It can also be
used on borders;
border: 1px solid
is equivalent to
border: 1px solid currentCo-
lor
. This can be quite useful when (un)setting a border's color via DOM scripting.
transparent
transparent
A special keyword that is a shorthand (just barely) for
rgba(0,0,0,0)
, which is the com-
puted value any time
transparent
is used.
