function showA() {
	document.getElementById("submenu_A")
			.style.visibility="visible";
	}
function shutA() {
	document.getElementById("submenu_A")
			.style.visibility="hidden";
	}

function showB() {
	document.getElementById("submenu_B")
			.style.visibility="visible";
	}
function shutB() {
	document.getElementById("submenu_B")
			.style.visibility="hidden";
	}

function showD() {
	document.getElementById("submenu_D")
			.style.visibility="visible";
	}
function shutD() {
	document.getElementById("submenu_D")
			.style.visibility="hidden";
	}