Index: wp-content/themes/twentytwelve/navigation.js
===================================================================
--- wp-content/themes/twentytwelve/navigation.js	(revision 20008)
+++ wp-content/themes/twentytwelve/navigation.js	(working copy)
@@ -8,11 +8,11 @@
 	    timeout = false;
 
 	$.fn.smallMenu = function() {
-		$( masthead ).find( '.site-navigation' ).removeClass( 'main-navigation' ).addClass( 'main-small-navigation' );
-		$( masthead ).find( '.site-navigation h3' ).removeClass( 'assistive-text' ).addClass( 'menu-toggle' );
+		masthead.find( '.site-navigation' ).removeClass( 'main-navigation' ).addClass( 'main-small-navigation' );
+		masthead.find( '.site-navigation h3' ).removeClass( 'assistive-text' ).addClass( 'menu-toggle' );
 
 		$( '.menu-toggle' ).click( function() {
-			$( masthead ).find( '.menu' ).toggle();
+			masthead.find( '.menu' ).toggle();
 			$( this ).toggleClass( 'toggled-on' );
 		} );
 	};
@@ -32,9 +32,9 @@
 			if ( browserWidth < 600 ) {
 				$.fn.smallMenu();
 			} else {
-				$( masthead ).find( '.site-navigation' ).removeClass( 'main-small-navigation' ).addClass( 'main-navigation' );
-				$( masthead ).find( '.site-navigation h3' ).removeClass( 'menu-toggle' ).addClass( 'assistive-text' );
-				$( masthead ).find( '.menu' ).removeAttr( 'style' );
+				masthead.find( '.site-navigation' ).removeClass( 'main-small-navigation' ).addClass( 'main-navigation' );
+				masthead.find( '.site-navigation h3' ).removeClass( 'menu-toggle' ).addClass( 'assistive-text' );
+				masthead.find( '.menu' ).removeAttr( 'style' );
 			}
 		}, 200 );
 	} );