generator-scratch/app/templates/scratch/src/js/skip-link-focus-fix.js

Scratch is a starter theme generator based on _s and Foundation. It's a theme meant for hacking so don't use it as a Parent Theme. Instead try turning it into the next, most awesome, WordPress theme out there.

/**
 * File skip-link-focus-fix.js.
 *
 * Helps with accessibility for keyboard only users.
 *
 * Learn more: https://git.io/vWdr2
 */
( function() {
	var isIe = /(trident|msie)/i.test( navigator.userAgent );

	if ( 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
		);
	}
} )();