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_s/js/navigation.js

82 lines
2.2 KiB
JavaScript

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