      }, // toggle chalkboard when 'b' is pressed
                46: function () {
                    RevealChalkboard.clear()
                }, // clear chalkboard when 'DEL' is pressed
                8: function () {
                    RevealChalkboard.reset()
                }, // reset chalkboard data on current slide when 'BACKSPACE' is pressed
                68: function () {
                    RevealChalkboard.download()
                }, // downlad recorded chalkboard drawing when 'd' is pre