function stop() {
    var audioPlayer = document.getElementsByTagName('audio')[0]; audioPlayer.pause(); audioPlayer.currentTime = 0;
}
 

function stop() { var audioPlayer = document.getElementsByTagName('audio'); addEventListener('loadedmetadata', function() { this.currentTime = 0; }, false); }
 

    <input type="button" value="play" id="playBtn" />
    <input type="button" value="pause" id="pauseBtn" />
    <input type="button" value="stop" id="stopBtn" />

 var source = "http://www.giorgiosardo.com/HTML5/audio/audio/sample.mp3"
    var audio = document.createElement("audio");
    audio.src = source;
    
    $("#playBtn").click(function () {  
            audio.play();
    });
    
    $("#pauseBtn").click(function () {
        audio.pause();
    });
    
    $("#stopBtn").click(function () {
        audio.pause();
        audio.currentTime = 0;
    });