82 lines
2.3 KiB
JavaScript
82 lines
2.3 KiB
JavaScript
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/**
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* File navigation.js.
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*
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* Handles toggling the navigation menu for small screens and enables TAB key
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* navigation support for dropdown menus.
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*/
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( function() {
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var container, button, menu, links, subMenus, i, len;
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container = document.getElementById( 'site-navigation' );
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if ( ! container ) {
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return;
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}
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button = container.getElementsByTagName( 'button' )[0];
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if ( 'undefined' === typeof button ) {
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return;
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}
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menu = container.getElementsByTagName( 'ul' )[0];
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// Hide menu toggle button if menu is empty and return early.
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if ( 'undefined' === typeof menu ) {
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button.style.display = 'none';
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return;
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}
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menu.setAttribute( 'aria-expanded', 'false' );
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if ( -1 === menu.className.indexOf( 'nav-menu' ) ) {
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menu.className += ' nav-menu';
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}
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button.onclick = function() {
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if ( -1 !== container.className.indexOf( 'toggled' ) ) {
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container.className = container.className.replace( ' toggled', '' );
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button.setAttribute( 'aria-expanded', 'false' );
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menu.setAttribute( 'aria-expanded', 'false' );
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} else {
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container.className += ' toggled';
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button.setAttribute( 'aria-expanded', 'true' );
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menu.setAttribute( 'aria-expanded', 'true' );
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}
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};
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// Get all the link elements within the menu.
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links = menu.getElementsByTagName( 'a' );
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subMenus = menu.getElementsByTagName( 'ul' );
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// Set menu items with submenus to aria-haspopup="true".
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for ( i = 0, len = subMenus.length; i < len; i++ ) {
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subMenus[i].parentNode.setAttribute( 'aria-haspopup', 'true' );
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}
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// Each time a menu link is focused or blurred, toggle focus.
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for ( i = 0, len = links.length; i < len; i++ ) {
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links[i].addEventListener( 'focus', toggleFocus, true );
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links[i].addEventListener( 'blur', toggleFocus, true );
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}
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/**
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* Sets or removes .focus class on an element.
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*/
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function toggleFocus() {
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var self = this;
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// Move up through the ancestors of the current link until we hit .nav-menu.
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while ( -1 === self.className.indexOf( 'nav-menu' ) ) {
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// On li elements toggle the class .focus.
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if ( 'li' === self.tagName.toLowerCase() ) {
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if ( -1 !== self.className.indexOf( 'focus' ) ) {
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self.className = self.className.replace( ' focus', '' );
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} else {
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self.className += ' focus';
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}
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}
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self = self.parentElement;
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}
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}
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} )();
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