Stop embedded audio with javascript

That didn't seem to work. Maybe I'm not putting the code in the right place. Also, the 'close_sample' button is not part of the animation so will the javascript listen for the close_sample button even if it's not part of the HTML5 animation?

document.addEventListener("DOMContentLoaded", function(event) {

window.parent.window.getElementById("close_sample").addEventListener( "click", stop, false);

var music = document.getElementById('music'); // id for audio element
var pButton = document.getElementById('pButton'); // play button
var sButton = document.getElementById('sButton'); // stop button

// play button event listenter
pButton.addEventListener("click", play);

// stop button event listener
sButton.addEventListener("click", stop);

//Play and Pause
function play() {
// start music
if (music.paused) {
music.play();
// remove play, add pause
pButton.className = "";
pButton.className = "pause";
} else { // pause music
music.pause();
// remove pause, add play
pButton.className = "";
pButton.className = "play";
}
}

//Stop
function stop() {
if (music.play) {
music.pause();
music.currentTime = 0;
// remove pause, add play
pButton.className = "";
pButton.className = "play";
}
}
/* DOMContentLoaded*/
});