<button onClick="rotatePrime(0);">Prime Slide Show</button>

var audioFile = new Array("a1.mp3","a2.mp3","a3.mp3");
var audio = new Array;

    for (i=0; i<audioFile.length; i++) {
      audio[i]= new Audio("Audio/"+audioFile[i]);
      audio[i].load();
    }

    function rotatePrime() {
            audio[0].play();
            audio[0].onended=setTimeout(function(){audio[1].play();}, 2000);
            audio[1].onended=setTimeout(function(){audio[2].play();}, 2000);
    }