function toggleMenu()
{
    var menu = document.getElementById('main_menu');
    if (menu.style.display == "none") {
        menu.style.display = "block";
    } else {
        menu.style.display = "none";
    }
}

function toggleMenu()
{
    var menu = document.getElementById('main_menu');
    if (menu.style.display == "none" || menu.style.display == "") {
        menu.style.display = "block";
    } else {
        menu.style.display = "none";
    }
}

Fix foldable menu only shown on second click glitch.
Fix foldable menu only shown on second click glitch.
