function showMenu(id){
	var c = document.getElementById(id + '-ddcontent');
	c.style.display = 'inline';
	c.style.visibility = 'visible';
}
function hideMenu(id){
	var c = document.getElementById(id + '-ddcontent');
	c.style.display = 'none';
	c.style.visibility = 'hidden';
}

// for test.
//window.onload = function(){showMenu('item12');}