var styleObj = ".style";

function popUpMenu(currID) {
var gi = "document.getElementById(currID)";
var popUpWin = eval(gi + styleObj);
popUpWin.visibility = "visible";
}
function popDownMenu(currID) {
var gi = "document.getElementById(currID)";
var popDownWin = eval(gi + styleObj);
popDownWin.visibility = "hidden";
}