wp-content/themes/twentyseventeen/assets/js/skip-link-focus-fix.js

   1 /**
   2  * File skip-link-focus-fix.js.
   3  *
   4  * Helps with accessibility for keyboard only users.
   5  *
   6  * Learn more: https://git.io/vWdr2
   7  */
   8 (function() {
   9         var isIe = /(trident|msie)/i.test( navigator.userAgent );
  10
  11         if ( isIe && document.getElementById && window.addEventListener ) {
  12                 window.addEventListener( 'hashchange', function() {
  13                         var id = location.hash.substring( 1 ),
  14                                 element;
  15
  16                         if ( ! ( /^[A-z0-9_-]+$/.test( id ) ) ) {
  17                                 return;
  18                         }
  19
  20                         element = document.getElementById( id );
  21
  22                         if ( element ) {
  23                                 if ( ! ( /^(?:a|select|input|button|textarea)$/i.test( element.tagName ) ) ) {
  24                                         element.tabIndex = -1;
  25                                 }
  26
  27                                 element.focus();
  28                         }
  29                 }, false );
  30         }
  31 })();