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

37 lines
1.1 KiB
JavaScript

/**
* Makes "skip to content" link work correctly in IE9, Chrome, and Opera
* for better accessibility.
*
* @link http://www.nczonline.net/blog/2013/01/15/fixing-skip-to-content-links/
*/
( function() {
var isWebkit = navigator.userAgent.toLowerCase().indexOf( 'webkit' ) > -1,
isOpera = navigator.userAgent.toLowerCase().indexOf( 'opera' ) > -1,
isIE = navigator.userAgent.toLowerCase().indexOf( 'msie' ) > -1;
if ( ( isWebkit || isOpera || isIE ) && document.getElementById && window.addEventListener ) {
window.addEventListener( 'hashchange', function() {
var id = location.hash.substring( 1 ),
element;
if ( ! ( /^[A-z0-9_-]+$/.test( id ) ) ) {
return;
}
element = document.getElementById( id );
if ( element ) {
if ( ! ( /^(?:a|select|input|button|textarea)$/i.test( element.tagName ) ) ) {
element.tabIndex = -1;
}
element.focus();
// Repositions the window on jump-to-anchor to account for admin bar and border height.
window.scrollBy( 0, -53 );
}
}, false );
}
} )();