АндрейD,
работает?
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<input type="submit" value="1" id="a">
<script>
var a = document.getElementById('a');
a.onclick = go;
function go() {
alert(a.getAttribute('value'));
}
</script>
</body>
</html>