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.
(function ( $, mw ) {
    var ns = mw.config.get('wgCanonicalNamespace');
    if (ns === "Special")
        return;  // no links for special pages

    mw.loader.using(["mediawiki.util"]).then(function () {
        var title = mw.config.get('wgTitle');
        if (ns !== "")
            title = title.replace(/^.*\//, "");  // subpage name only
 
        var query = encodeURIComponent(title); 
        mw.util.addPortletLink('p-tb', 
            'https://www.google.com/search?as_eq=wikipedia&q=%22'+query+'%22&num=50',
            'Google', 
            't-googlesearch', 
            'Search Google for "'+title+'"', 'G');
        mw.util.addPortletLink('p-tb', 
            'https://www.google.com/search?tbm=nws&q=%22'+query+'%22+-wikipedia',
            'news', 
            't-googlenewssearch', 
            'Search Google News for "'+title+'"');
        mw.util.addPortletLink('p-tb', 
            'https://www.google.com/search?&q=%22'+query+'%22+site:news.google.com/newspapers&source=newspapers',
            'newspapers', 
            't-googlenewspapersearch', 
            'Search newspapers for "'+title+'"');
        mw.util.addPortletLink('p-tb', 
            'https://www.google.com/search?tbs=bks:1&q=%22'+query+'%22+-wikipedia',
            'books', 
            't-googlebookssearch', 
            'Search Google Books for "'+title+'"');
        mw.util.addPortletLink('p-tb', 
            'https://scholar.google.com/scholar?q=%22'+query+'%22',
            'scholar', 
            't-googlescholarsearch', 
            'Search Google Scholar for "'+title+'"');
        mw.util.addPortletLink('p-tb', 
            'https://www.jstor.org/action/doBasicSearch?Query=%22'+query+'%22&acc=on&wc=on',
            'JSTOR', 
            't-jstor', 
            'Search JSTOR for "'+title+'"');
    });
} (jQuery, mediaWiki ));

/*
$(function () {
    if (wgCanonicalNamespace == "Special")
        return;  // no links for special pages
    var title = wgTitle;
    if (wgCanonicalNamespace !== "")
        title = title.replace(/^.*\//, "");  // subpage name only
    var query = encodeURIComponent(title); 
    mw.util.addPortletLink('p-tb', 'https://www.google.com/search?as_eq=wikipedia&q=%22'+query+'%22&num=50',
                   'Google', 't-googlesearch', 'Search Google for "'+title+'"', 'G');
    mw.util.addPortletLink('p-tb', 'https://www.google.com/search?tbm=nws&q=%22'+query+'%22+-wikipedia',
                   'news', 't-googlenewssearch', 'Search Google News for "'+title+'"');
    mw.util.addPortletLink('p-tb', 'https://www.google.com/search?&q=%22'+query+'%22+site:news.google.com/newspapers&source=newspapers',
                   'newspapers', 't-googlenewspapersearch', 'Search newspapers for "'+title+'"');
    mw.util.addPortletLink('p-tb', 'https://www.google.com/search?tbs=bks:1&q=%22'+query+'%22+-wikipedia',
                   'books', 't-googlebookssearch', 'Search Google Books for "'+title+'"');
    mw.util.addPortletLink('p-tb', 'https://scholar.google.com/scholar?q=%22'+query+'%22',
                   'scholar', 't-googlescholarsearch', 'Search Google Scholar for "'+title+'"');
    mw.util.addPortletLink('p-tb', 'https://www.jstor.org/action/doBasicSearch?Query=%22'+query+'%22&acc=on&wc=on',
                   'JSTOR', 't-jstor', 'Search JSTOR for "'+title+'"');
});
*//*
https://www.google.com/search?as_eq=wikipedia&q=%22'+query+'%22&num=50
https://www.google.com/search?tbm=nws&q=%22'+query+'%22+-wikipedia
https://www.google.com/search?&q=%22'+query+'%22+site:news.google.com/newspapers&source=newspapers
https://www.google.com/search?tbs=bks:1&q=%22'+query+'%22+-wikipedia
https://scholar.google.com/scholar?q=%22'+query+'%22
https://www.jstor.org/action/doBasicSearch?Query=%22'+query+'%22&acc=on&wc=on
*/