I have seen many places using Math.floor() and Math.random()
like below
$(\'a.random-color\').hover(function() { //mouseove
Math.random will give you a floating point number between 0 (inclusive) and 1 (exclusive).
Multiplying that by 256 will give you a number in the range 0 (inclusive) through 256 (exclusive), but still floating point.
Taking the floor of that number will give you an integer between 0 and 255 (both inclusive).
It's the integer from 0 to 255 that you need to construct RGB values like rgb(72,25,183).