I thing that is something inside this function:
function initMainNavigation( container ) {
// Add dropdown toggle that displays child menu items.
var dropdownToggle = $( '<button />', {
'class': 'dropdown-toggle',
'aria-expanded': false
} ).append( $( '<span />', {
'class': 'screen-reader-text',
text: screenReaderText.expand
} ) );
container.find( '.menu-item-has-children > a' ).after( dropdownToggle );
// Toggle buttons and submenu items with active children menu items.
container.find( '.current-menu-ancestor > button' ).addClass( 'toggled-on' );
container.find( '.current-menu-ancestor > .sub-menu' ).addClass( 'toggled-on' );
// Add menu items with submenus to aria-haspopup="true".
container.find( '.menu-item-has-children' ).attr( 'aria-haspopup', 'true' );
container.find( '.dropdown-toggle' ).click( function( e ) {
var _this = $( this ),
screenReaderSpan = _this.find( '.screen-reader-text' );
e.preventDefault();
_this.toggleClass( 'toggled-on' );
_this.next( '.children, .sub-menu' ).toggleClass( 'toggled-on' );
// jscs:disable
_this.attr( 'aria-expanded', _this.attr( 'aria-expanded' ) === 'false' ? 'true' : 'false' );
// jscs:enable
screenReaderSpan.text( screenReaderSpan.text() === screenReaderText.expand ? screenReaderText.collapse : screenReaderText.expand );
} );
}
initMainNavigation( $( '.main-navigation' ) );
masthead = $( '#masthead' );
menuToggle = masthead.find( '#menu-toggle' );
siteHeaderMenu = masthead.find( '#site-header-menu' );
siteNavigation = masthead.find( '#site-navigation' );
socialNavigation = masthead.find( '#social-navigation' );