Poll song name from remote service using jQuery

gistfile1.js

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.js"></script>
<div id="song">Loading song...</div>

$(document).ready(function() {
	$.post(
		'http://example.com/get/song',
		function(data) {
			if (data.song !== '') {
				$('#song').text(data.song);
			}
		}
	);
	(function poll() {
		setTimeout(function(){
			var songRequest = $.post('http://example.com/get/song');
			songRequest.success(function(data) {
				if (data.song === '') {
					var song = 'Service temporarily unavailable';
				} else {
					var song = data.song;
				}
				$('#song').text(song);
				poll();
			});
			songRequest.error(function(data) {
				$('#song').text('Service temporarily unavailable');
				poll();
			});
		}, 3000);
	})();
});