JavaScript: Assignment: - [E] Implement and test stopCountDownTimer() method per comments. - [F] Implement and test displayCountDown() method per comments - [G] Implement and test countDown() method per comments. countDown: function() { // TODO [G]: Decrement and display count down value and reach 0 stop timer  // Hint: You will need to call displayCountdown() and stopCountDownTimer() displayCountDown: function() { // TODO [F]: Update countdown span element with current countdown value  // Hint: Get a reference to count down span and set the span textContent property with the counter }, startCountDownTimer: function(start) { this._startCount = start; this._counter = this._startCount; this.displayCountDown(); this._intervalID = setInterval(this.countDown.bind(this), 1000); }, stopCountDownTimer: function() { // TODO [E]: Stop timer using object timer property  // Hint: Will need to call clearInterval() },