MediaWiki:Common.js

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/* Any JavaScript here will be loaded for all users on every page load. */
mw.loader.using('mediawiki.util').done(function () {
    if (window.matchMedia("(max-width: 768px)").matches) {
        var infobox = document.querySelector('.infobox');
        var content = document.querySelector('.content');
        if (infobox && content) {
            content.parentNode.insertBefore(content, infobox.nextSibling);
        }
    }
});