what are the colour codes used ? in HTML for various purposes ..
the color codes of rgb or hexadecimal codes don't just give the the limitation to naming a color but in order for you to create your own color with the blends of red, green and blue, they are Also in hexadecimal because the computer understands binary, octadecimal and hexadecimal
please check http://www.w3schools.com/colors/colors_picker.asp
As far as I know, RGB and Hex codes are the very common color codes used in HTML.