https://academeblog.org/wp-content/themes/expound/js/skip-link-focus-fix.js?ver=20130115

1( function() {
2	var is_webkit = navigator.userAgent.toLowerCase().indexOf( 'webkit' ) > -1,
3	    is_opera  = navigator.userAgent.toLowerCase().indexOf( 'opera' )  > -1,
4	    is_ie     = navigator.userAgent.toLowerCase().indexOf( 'msie' )   > -1;
5
6	if ( ( is_webkit || is_opera || is_ie ) && 'undefined' !== typeof( document.getElementById ) ) {
7		var eventMethod = ( window.addEventListener ) ? 'addEventListener' : 'attachEvent';
8		window[ eventMethod ]( 'hashchange', function() {
9			var element = document.getElementById( location.hash.substring( 1 ) );
10
11			if ( element ) {
12				if ( ! /^(?:a|select|input|button|textarea)$/i.test( element.tagName ) )
13					element.tabIndex = -1;
14
15				element.focus();
16			}
17		}, false );
18	}
19})();