var screenshot = 1;
var numScreenshots = 4;
var screenDescription1 = "Ring your iPhone or iPod Touch to play";
var screenDescription2 = "Choose a song to play from the start screen";
var screenDescription3 = "See your score, from a broken to a golden handbell";
var screenDescription4 = "Playing Jingle Bells";

function showPrev() {
	screenshot--;
	if (screenshot < 1)
		screenshot = numScreenshots;
	document.getElementById("screenshot").src = "http://likethought.com/touch/handbell/images/screenshots/" + screenshot + ".png";
	document.getElementById("description").innerHTML = eval("screenDescription" + screenshot);
}

function showNext() {
	screenshot++;
	if (screenshot > numScreenshots)
		screenshot = 1;
	document.getElementById("screenshot").src = "http://likethought.com/touch/handbell/images/screenshots/" + screenshot + ".png";
	document.getElementById("description").innerHTML = eval("screenDescription" + screenshot);
}