This section lists the predefined colours that are defined in HTML 4.01. The document used for this section was http://www.w3.org/TR/html401/types.html#h-6.5.
Aqua = #00FFFF
Black = #000000
Blue = #0000FF
Fuchsia = #FF00FF
Gray = #808080
Green = #008000
Lime = #00FF00
Maroon = #800000
Navy = #000080
Olive = #808000
Purple = #800080
Red = #FF0000
Silver = #C0C0C0
Teal = #008080
White = #FFFFFF
Yellow = #FFFF00Cascading Style Sheets level 2 introduced system colours, that are unique to the operating system that the user has. Below are listed the possible values with a description of what they are (courtesy of http://www.w3.org/TR/REC-CSS2/ui.html#system-colors).
ActiveBorder
ActiveCaption
AppWorkspace
Background
ButtonFace
ButtonHighlight
ButtonShadow
ButtonText
CaptionText
GrayText
Highlight
HighlightText
InactiveBorder
InactiveCaption
InactiveCaptionText
InfoBackground
InfoText
Menu
MenuText
Scrollbar
ThreeDDarkShadow
ThreeDFace
ThreeDHighlight
ThreeDLightShadow
ThreeDShadow
Window
WindowFrame
WindowTextIf you do not have a JavaScript-enabled brower, or would prefer to just see a list of the web-safe colours, you can view the web-safe colours page.