https://www.backlinkdev.ir/path/wp-content/themes/twentyfifteen/js/skip-link-focus-fix.js?ver=20141028

1/**
2 * Makes "skip to content" link work correctly in IE9, Chrome, and Opera
3 * for better accessibility.
4 *
5 * @link http://www.nczonline.net/blog/2013/01/15/fixing-skip-to-content-links/
6 */
7
8( function() {
9	var ua = navigator.userAgent.toLowerCase();
10
11	if ( ( ua.indexOf( 'webkit' ) > -1 || ua.indexOf( 'opera' ) > -1 || ua.indexOf( 'msie' ) > -1 ) &&
12		document.getElementById && window.addEventListener ) {
13
14		window.addEventListener( 'hashchange', function() {
15			var element = document.getElementById( location.hash.substring( 1 ) );
16
17			if ( element ) {
18				if ( ! /^(?:a|select|input|button|textarea)$/i.test( element.nodeName ) ) {
19					element.tabIndex = -1;
20				}
21
22				element.focus();
23			}
24		}, false );
25	}
26} )();