function navRoll(obj) {
	var mydiv = 'navArea-'+obj;

	// don't turn off the object we're trying to turn on
	if (document.currentRoll && document.currentRoll == obj) return;

	// un-roll the current item
	if (document.currentRoll) {
		document.getElementById('navArea-'+document.currentRoll).style.backgroundColor='transparent';
		document.getElementById('menu-'+document.currentRoll).style.display='none';
		document.currentRoll = null;
	}

	if (document.getElementById(mydiv)) {
		document.getElementById(mydiv).style.backgroundColor='#aeaa99';
		document.getElementById('menu-'+obj).style.display='inline';
		document.currentRoll = obj;
	}
}

function homePicture() {
	var imgCount = 15; // number of image named home_backX.jpg, where X is a serialized integer (home_back1.jpg, home_back2.jpg, ...)
	var img = 'userFiles/images/homeBackgrounds/home_back'+Math.round((imgCount-1)*Math.random())+'.jpg';
	if (document.getElementById('navMenu')) {
		document.getElementById('navMenu').style.backgroundImage="url("+img+")";
	}
}