Web safe color picker
In HTML, colors are represented either as hexadecimal values (such as #FF0000) or as color names (red). Web-safe colors are those that appear the same in Netscape Navigator and Microsoft Internet Explorer on both Windows and Macintosh systems when running in 256-color mode. The conventional wisdom is that there are 216 common colors, and that any hexadecimal value that combines the pairs 00, 33, 66, 99, CC, or FF (RGB values 0, 51, 102, 153, 204, and 255, respectively) represents a web-safe color.
However, testing has shown that there are only 212 web-safe colors, not all 216, because Windows Internet Explorer cannot correctly render the colors #0033FF (0,51,255), #3300FF (51,0,255), #00FF33 (0,255,51), and #33FF00 (51,255,0).
When web browsers were first developing their appearance, most computers displayed only 265 colors (8-bit). Today, most computers can display thousands or millions of colors (16-bit and 32-bit), so if you are developing sites for users with current computer systems, there is no reason to use the browser-safe palette.
One case where you would use a web-safe color palette is when developing sites for alternative web devices, such as PDA and cell phone displays. Many of these devices offer only black and white (1-bit) or 256-color (8-bit) displays.