function changeMenu(id){
	document.getElementById("menu"+id).style.backgroundImage = 'url(./images/menu'+id+'.jpg)';
	document.getElementById("menu"+id).className = "menu_text_selected";
}

function restoreMenu(id){
	document.getElementById("menu"+id).style.backgroundImage = 'none';
	document.getElementById("menu"+id).className = "menu_text";
}