function display(id){
     hide_all();
     var submenu = document.getElementById('submenu_'+id);
     submenu.style.display = "block";
}
function hide_all(){
	for (i=1;i<8;i++) {
	    var submenu = document.getElementById('submenu_'+i);
	    if( submenu )
	         submenu.style.display = "none";
	}
}