var backImage = new Array();			
backImage[0] = "./images/background1.jpg";
backImage[1] = "./images/background2.jpg";
backImage[2] = "./images/background3.jpg";
backImage[3] = "./images/background4.jpg";

var currentImage = -1;
var nextImage = 0;

function changeBGImage(){
	// generate random next image
	nextImage = Math.floor(Math.random()*4);
	// check random image is the current image
	if(nextImage == currentImage) changeBGImage();
	else {
		// set the new image
		document.body.background = backImage[nextImage];
		currentImage = nextImage;
	}
}

function loadDiv(divId) {
	// change bg image
	changeBGImage();
	// hide all divs
	document.getElementById("welcome").style.display="none";
	document.getElementById("biography").style.display="none";
	document.getElementById("lyrics").style.display="none";
	document.getElementById("shows").style.display="none";
	document.getElementById("links").style.display="none";
	// show argued div
	document.getElementById(divId).style.display="block";
}