I'm wondering, how would I make an app that plays audio files using the keys on the number pad? Specifically, I want to make an app that triggers "Rotary Pulse 1" by pressing 1 on the numeric keypad, all the way up to "Rotary Pulse 0" on the 0 key. A dial tone will be toggled on by pressing the spacebar, which will begin with a "receiver pickup" noise. The dial tone turns off when digits are dialed via the numeric keypad. If you press the spacebar either when the dial tone is on, or after dialing a number, a "Receiver Hang Up" noise will be triggered. With the rotary dial sounds, the dial turning to the fingerhole is triggered at key down, and the release of the dial returning to the resting position will be triggered by releasing of the number corresponding to the fingerhole (1, 2, 3, 4, 5, 6, 7, 8, 9, 0). This will be accompanied by the internal sound of the dial pulses as heard in a telephone. What is the code I would use to make this audio app using HTML?