Hexadecimal color values are also supported in all browsers.
A hexadecimal color is specified with: #RRGGBB.
RR (red), GG (green) and BB (blue) are hexadecimal integers between 00 and FF specifying the intensity of the color.
For example, #0000FF is displayed as blue, because the blue component is set to its highest value (FF) and the others are set to 00.
Try it Yourself
Hexadecimal color values are supported in all browsers.