function show_hide_div(id) 	{
	document.getElementById(id).style.display = (document.getElementById(id).style.display == "none") ? "block" : "none";
	}
	

function hide_submenu(id) 	{
	var submenu = document.getElementById(id);
	var submenu_div = submenu.getElementsByTagName('div');
	for (var k = 0; k < submenu_div.length; k++) 
		submenu_div[k].style.display = 'none';
	}
		

function show_submenu(id) 	{
	if(document.getElementById(id))
		document.getElementById(id).style.display = "block";
	}
	
function show_hide_submenu(id_submenu, id_div) 	{
	hide_submenu(id_submenu);
	document.getElementById(id_div).style.display = "block";
	}



function clearField(field) {
	if (field.value == field.defaultValue) {
		field.value = "";
		}
	}

function checkField(field) {
	if (field.value == "") {
		field.value = field.defaultValue;
		}
	}