// open hidden layer
function mopen(id)
{
var menuitem = document.getElementById(id);

	// close old layer
	if(menuitem) menuitem.style.visibility = 'hidden';

	// get new layer and show it
	if(menuitem) menuitem.style.visibility = 'visible';

}

// close showed layer
function mclose(id)
{
var menuitem = document.getElementById(id);

	if(menuitem) menuitem.style.visibility = 'hidden';
}

// close layer when click-out
document.onclick = mclose;