function ChangeBackground() {
	//check for cookie
	if(document.readCookie("hp_image") != undefined) {
		//show next image
		var body_element = document.$("tmpl_body");
		var next_image = NextImageNumber(document.readCookie("hp_image"));
		body_element.style.backgroundImage = "url(/_IMAGES/Templates/www_main/hp_befree_"+ next_image +".jpg)";
		document.createCookie("hp_image",next_image);
	}
	else {
		//create the first cookie
		document.createCookie("hp_image","01");
	}
}

function NextImageNumber(current) {
	var nextImageNumber = "";
	switch(current) {
		case "01":
			nextImageNumber = "02";
			break;
		case "02":
			nextImageNumber = "03";
			break;
		case "03":
			nextImageNumber = "04";
			break;
		case "04":
			nextImageNumber = "01";
			break;
		default:
			nextImageNumber = "01";
			break;
	}
	return nextImageNumber;
}