https://www.editorialgeu.com/blog/wp-content/themes/_tk-geu/includes/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})();