1 /**

     2  * navigation.js

     3  *

     4  * Handles toggling the navigation menu for small screens.

     5  */

     6 ( function() {

     7 	var nav = document.getElementById( 'site-navigation' ), button, menu;

     8 	if ( ! nav )

     9 		return;

    10 	button = nav.getElementsByTagName( 'h3' )[0];

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

    12 	if ( ! button )

    13 		return;

    14 

    15 	// Hide button if menu is missing or empty.

    16 	if ( ! menu || ! menu.childNodes.length ) {

    17 		button.style.display = 'none';

    18 		return;

    19 	}

    20 

    21 	button.onclick = function() {

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

    23 			menu.className = 'nav-menu';

    24 

    25 		if ( -1 != button.className.indexOf( 'toggled-on' ) ) {

    26 			button.className = button.className.replace( ' toggled-on', '' );

    27 			menu.className = menu.className.replace( ' toggled-on', '' );

    28 		} else {

    29 			button.className += ' toggled-on';

    30 			menu.className += ' toggled-on';

    31 		}

    32 	};

    33 } )();