function showMenu(txtID) {
	document.getElementById(txtID).style.visibility = "";
}

function closeMenu(txtID) {
	document.getElementById(txtID).style.visibility = "hidden";
}

function changeStyle(txtID) {
	document.getElementById(txtID).className = "menu_over02";
}

function normalStyle(txtID) {
	document.getElementById(txtID).className = "menu_over01";
}