/**
 * navigation.js
 *
 * Handles toggling the navigation menu for small screens.
 */
(function () {
    var container, button, menu;

    container = document.getElementById('site-navigation');
    if (!container)
        return;

    button = container.getElementsByTagName('h1')[0];
    if ('undefined' === typeof button)
        return;

    menu = container.getElementsByTagName('ul')[0];

    // Hide menu toggle button if menu is empty and return early.
    if ('undefined' === typeof menu) {
        button.style.display = 'none';
        return;
    }

    if (-1 === menu.className.indexOf('nav-menu'))
        menu.className += ' nav-menu';

    button.onclick = function () {
        if (-1 !== container.className.indexOf('toggled'))
            container.className = container.className.replace(' toggled', '');
        else
            container.className += ' toggled';
    };
})();