wp-content/themes/twentysixteen/js/skip-link-focus-fix.js

   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 isWebkit = navigator.userAgent.toLowerCase().indexOf( 'webkit' ) > -1,
  10                 isOpera  = navigator.userAgent.toLowerCase().indexOf( 'opera' )  > -1,
  11                 isIE     = navigator.userAgent.toLowerCase().indexOf( 'msie' )   > -1;
  12
  13         if ( ( isWebkit || isOpera || isIE ) && document.getElementById && window.addEventListener ) {
  14                 window.addEventListener( 'hashchange', function() {
  15                         var id = location.hash.substring( 1 ),
  16                                 element;
  17
  18                         if ( ! ( /^[A-z0-9_-]+$/.test( id ) ) ) {
  19                                 return;
  20                         }
  21
  22                         element = document.getElementById( id );
  23
  24                         if ( element ) {
  25                                 if ( ! ( /^(?:a|select|input|button|textarea)$/i.test( element.tagName ) ) ) {
  26                                         element.tabIndex = -1;
  27                                 }
  28
  29                                 element.focus();
  30
  31                                 // Repositions the window on jump-to-anchor to account for admin bar and border height.
  32                                 window.scrollBy( 0, -53 );
  33                         }
  34                 }, false );
  35         }
  36 } )();