Color is defined as a six digit hexadecimal number in HTML, Every number resembles a color, to inform the browser to interpret the following number as a hexadecimal number you will need to insert a # before the number, thus #FFFFFF is white and #000000 is black.

How many colors can be defined in HTML a?

The Hexadecimal number FFFFFF is equivalent to 16777215 in decimal, This means you can specify close to 17 million colors with HTML, But this will not reflect on your monitor unless you have a video card and a monitor to reflect them.

So what is the relation between the color i see and the number ?

Simply put, all colors can be obtained from a mix of Red Green And Blue, with this system, you can specify 256 (FF) of red, another 256 or green and another of 256 of blue, For example what we can call all BLUE is 0000FF (red and green set to 0 and blue set to FF(hex)

What is a hexadecimal number? Click here for an expiation in a new window

The following is a color code table with every sell in the color resembled by the number in it.
Numbers are spaced with 33 increments for every row or column, the idea of this is from another website, to save space, If you like you can access a larger plate (very big and dynamically generated) here.