var maxMenu = 4;
var gCurrentMenuID = null;

// display menu
function viewMenu(objID){
	hideMenu();
	document.getElementById(objID).style.visibility = "visible";
	gCurrentMenuID = objID;
}

// hide menu
function hideMenu(){
	for (var i=1; i<=maxMenu; i++) document.getElementById("pMenu"+i).style.visibility = "hidden";
	gCurrentMenuID = null;
}