var curPosition=-140;
var curMenu;
var slider;
function showMenu(selectedMenu) {
clearInterval(slider);
curMenu = document.getElementById(selectedMenu);
slider = setInterval("show()", 10);
}

function show() {
if (curPosition < -6) {
curPosition = curPosition + 2;
curMenu.style.left = curPosition + "px";
}
}

function hideMenu(selectedMenu) {
clearInterval(slider);
curMenu = document.getElementById(selectedMenu);
slider = setInterval("hide()", 10);
}

function hide() {
if (curPosition > -140) {
curPosition = curPosition - 2;
curMenu.style.left = curPosition + "px";
}
}