var timer_id = null;

function OpenMenu(id){ 
	if( timer_id ) {
		clearTimeout( timer_id );
		timer_id = null;
	}
	document.getElementById( id ).style.visibility = 'visible';
}
function CloseMenu(id){ 
	timer_id = setTimeout( "hiddenMenu('"+id+"')", 100 );
}
function hiddenMenu(id){ 
	document.getElementById( id ).style.visibility = 'hidden';
	timer_id = null;
}