MediaWiki:Gadget-vector-headanchor.js

 /*!
  * Vector HeadAnchors gadget
  *
  * Copyright 2013 Timo Tijhof, https://mediawiki.org/wiki/MediaWiki:Gadget-vector-headanchor.js
  * SPDX-License-Identifier: MIT
  * License: https://opensource.org/licenses/MIT
  */

 mw.hook('wikipage.content').add(function($content){
 $content.find('div.mw-heading').each(function(i,heading){
 varel=heading.querySelector('[id]:is(h1,h2,h3,h4,h5,h6)');
 if(!el||heading.querySelector('.tpl-vheadanchor')){
 // No anchor possible, or anchor already inserted
 return;
 }

 // Support legacy Parser (wgParserEnableLegacyHeadingDOM=false):
 // <div class=mw-heading><h2 id>Headline</h2></div>
 //
 // Support Parsoid:
 // <section>
 // <div class=mw-heading><h2 id>Headline</h2></div>
 // </section>
 //
 // Support DiscussionTools:
 // - DiscussionTools wraps H2 into DIV.mw-heading, setting overflow:hidden on
 // the outer DIV instead of H2. Our override has to match to avoid clipping
 // the anchor.
 // - DiscussionTools inserts an element with [id] before H2, so the above selector
 // for `el` must hardcode all heading tags instead of just [id].
 // <div class=mw-heading>
 // <span id="ooui-php-1" class="ext-discussiontools-init-section-subscribeButton"><a href>Subscribe</a></span>
 // <h2 id><span>...</span>Headline<span>...</span></h2>
 // </div>
 heading.classList.add('tpl-vheadanchor-heading');

 // Insert anchor.
 anchor=document.createElement('a');
 anchor.href='#'+el.id;
 anchor.textContent='#';
 anchor.title='Link to this section';
 anchor.className='tpl-vheadanchor';
 heading.insertBefore(anchor,el.nextSibling);
 });
 });