Note: After saving, you have to bypass your browser's cache to see the changes. Google Chrome, Firefox, Microsoft Edge and Safari: Hold down the ⇧ Shift key and click the Reload toolbar button. For details and instructions about other browsers, see Wikipedia:Bypass your cache.
/* [[Wikipedia:WikiProject User scripts/Scripts/Add purge to tabs|addPurge]] */
$(function () {
    var hist; var url;
    if (!(hist = document.getElementById('ca-history') )) return;
    if (!(url = hist.getElementsByTagName('a')[0] )) return;
    if (!(url = url.href )) return;
    mw.util.addPortletLink('p-cactions', url.replace(/([?&]action=)history([&#]|$)/, '$1purge$2'),
                   'purge', 'ca-purge', 'Purge server cache for this page', '0');
});

// includeScript('MediaWiki:WikiProject User scripts/Scripts/Multi-NS search.js');