// after every second timer

        setInterval(randomRgb, 1);

​

        function randomRgb() {

            // create the rgb string

            var col =  "rgb("+ randomColor(255) + "," + randomColor(255)+ ","+ randomColor(255) + ")";

​

            //change the text color with the new random color

            document.getElementById("one").style.background.color = col;

        }

        function randomColor(num) {            

            return Math.floor(Math.random() * num);

        }