This works for some common colors such black or white, because black is black and white is white. You might think of one shade of blue as blue and your friend might think of another.
Browsers are the same way.
What Internet Explorer thinks of as blue might be very different than what Netscape Navigator does, and different versions of the same browser may look different. There is a way around this problem. The solution is to state the color specifically using a number rather than a name. We use Hexadecimal numbers to indicate color values. If you want more on what hexadecimals are, then scroll down to the bottom of this page to find out.