diff -r f507feede89a -r 09a1c134465b web/wp-content/themes/twentytwelve/js/navigation.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/wp-content/themes/twentytwelve/js/navigation.js	Wed Dec 19 17:46:52 2012 -0800
@@ -0,0 +1,33 @@
+/**
+ * navigation.js
+ *
+ * Handles toggling the navigation menu for small screens.
+ */
+( function() {
+	var nav = document.getElementById( 'site-navigation' ), button, menu;
+	if ( ! nav )
+		return;
+	button = nav.getElementsByTagName( 'h3' )[0];
+	menu   = nav.getElementsByTagName( 'ul' )[0];
+	if ( ! button )
+		return;
+
+	// Hide button if menu is missing or empty.
+	if ( ! menu || ! menu.childNodes.length ) {
+		button.style.display = 'none';
+		return;
+	}
+
+	button.onclick = function() {
+		if ( -1 == menu.className.indexOf( 'nav-menu' ) )
+			menu.className = 'nav-menu';
+
+		if ( -1 != button.className.indexOf( 'toggled-on' ) ) {
+			button.className = button.className.replace( ' toggled-on', '' );
+			menu.className = menu.className.replace( ' toggled-on', '' );
+		} else {
+			button.className += ' toggled-on';
+			menu.className += ' toggled-on';
+		}
+	};
+} )();
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