pen/assets/js/skip-link-focus-fix.js

/**
 * Helps with accessibility for keyboard only users.
 *
 * Learn more: https://git.io/vWdr2
 *
 * @package Pen
 */
;( function() {
	var isWebkit    = navigator.userAgent.toLowerCase().indexOf( 'webkit' ) > -1,
			isOpera = navigator.userAgent.toLowerCase().indexOf( 'opera' ) > -1,
			isIe    = navigator.userAgent.toLowerCase().indexOf( 'msie' ) > -1;

	if ( ( isWebkit || isOpera || isIe ) && document.getElementById && window.addEventListener ) {
		window.addEventListener(
			'hashchange',
			function() {
				var id = location.hash.substring( 1 ),
				element;

				if ( ! ( /^[A-z0-9_-]+$/.test( id ) ) ) {
					return;
				}

				element = document.getElementById( id );

				if ( element ) {
					if ( ! ( /^(?:a|select|input|button|textarea)$/i.test( element.tagName ) ) ) {
						element.tabIndex = -1;
					}

					element.focus();
				}
			},
			false
		);
	}
})();