function clear_menus() {
	
	var i=1;
	while (document.getElementById("item_" + i)) {
		document.getElementById("item_" + i).style.backgroundImage = "none";
		document.getElementById("span_item_" + i).style.backgroundImage = "none";
		document.getElementById("span_item_" + i).style.color = "#ffffff";
		
		i = i + 1;
	}
	
	document.getElementById("submenu").innerHTML = "";
}

function display_submenu(menu_number) {

	clear_menus();

	document.getElementById("item_" + menu_number).style.backgroundImage = "url(../images/main_menu_hover_left.jpg)";
	
	document.getElementById("span_item_" + menu_number).style.backgroundImage = "url(../images/main_menu_hover_bg.jpg)";
	document.getElementById("span_item_" + menu_number).style.backgroundPosition = "right";
	document.getElementById("span_item_" + menu_number).style.color = "#000000";
	
	document.getElementById("submenu").innerHTML = document.getElementById("submenu_" + menu_number).innerHTML;
	
}