Greasemonkey script to hide the "small" Wikipedia fundraiser banner

nofundraiser.js

// ==UserScript==
// @name         No Wikipedia fundraiser
// @namespace    http://chivil.com/
// @version      0.1
// @description  Should hide Wikipedia "small" banner on each page
// @author       Romuald Brunet
// @match        https://*.wikipedia.org/*
// @grant        none
// @run-at       document-end

// ==/UserScript==

function checkBanner() {
    if ( window.mw && mw.centralNotice && mw.centralNotice.bannerData ) {
        mw.centralNotice.bannerData.hideResult = true;
        /*
        if ( window.fundraisingBanner ) {
            fundraisingBanner.hide();
        }
        */
    } else if ( (new Date()).getTime() < giveup )  {
        window.setTimeout(checkBanner, 10);
    }

}
// Stop polling after 4 seconds
var giveup = (new Date()).getTime() + 4000;
window.setTimeout(checkBanner, 10);

Doesn't work