MediaWiki:Common.js

$(document).ready(function () {
    if (mw.config.get('wgPageName') !== 'Special:UserLogin') {
        // Move the tab bar (#vector-page-toolbar) BELOW your banner
        const tabs = document.querySelector('.vector-page-toolbar-container');
        const banner = document.createElement('div');
        banner.id = 'asx-top-banner';
        banner.innerHTML = '<img src="https://asxresearch.org/images/a/aa/ASX-Header-Banner2.png" alt="ASX Header">';
        
        // Insert banner BEFORE tab bar
        tabs.parentNode.insertBefore(banner, tabs);
    }
});