Stroy,
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<script>
var ms = 1000;
var number;
var interval;
function MP3(){
document.getElementById('player').play();
}
function setTime () {
number = document.getElementById('number').value;
}
function SetInterval(){
!number && setTime();
!+number && (number = 10);
number = number * ms;
MP3();
ClearInterval();
interval = window.setInterval(MP3, number);
}
function ClearInterval(){
window.clearInterval(interval);
}
</script>
<style type="text/css">
div{
margin: 0 auto;
width: 400px;
}
</style>
</head>
<body>
<div>Музыка
<audio id="player" src="http://boobooka.com/wp-content/uploads/2013/01/moneta.mp3" controls></audio>
<form action="mp3.html" onsubmit="return false" >
<input type="text" name="numb" id="number" value="10">
<input type="submit" value="установить время цикла" onclick="setTime()">
</form>
</div>
<button onclick="SetInterval()" value="">Запуск цикла</button><br>
<button onclick="ClearInterval()" value="">Прервать цикл</button>
</body>
</html>