This is achieved by entering in this field a formula whose result must be the name of a color in HTML, while integrating fields on the line in the context. For instance, if a green indicator is requested if A=1, a blue indicator if A=2, a red indicator if A=3 and a yellow indicator if A=4, a formula of the following type should be written:
string$(A=1,"green")+string$(A=2,"blue")+string$(A=3,"red")+string$(A=4,"yellow")
The names of the colors officially recognized by the HTML standard are the following:
aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white, yellow
There are some other colors most of which are recognized by HTML browsers (pink, gold, tomato, plum, violet, dark gray, to mention a few). Finally, it is always possible to describe a color using its hexadecimal code, for example, #FA8072 (for salmon).