Disable JavaScript Alert Boxes

Blocks annoying page-load alert boxes during the first 5 seconds

Verze ze dne 08. 05. 2026. Zobrazit nejnovější verzi.

K instalaci tototo skriptu si budete muset nainstalovat rozšíření jako Tampermonkey, Greasemonkey nebo Violentmonkey.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Violentmonkey.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Userscripts.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat manažer uživatelských skriptů.

(Už mám manažer uživatelských skriptů, nechte mě ho nainstalovat!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(Už mám manažer uživatelských stylů, nechte mě ho nainstalovat!)

// ==UserScript==
// @name         Disable JavaScript Alert Boxes
// @namespace    RGlzYWJsZSBqYXZhc2NyaXB0IGFsZXJ0IGJveGVz
// @version      1.1
// @description  Blocks annoying page-load alert boxes during the first 5 seconds
// @author       smed79
// @license      GPLv3
// @icon         https://i25.servimg.com/u/f25/11/94/21/24/x10.jpg
// @include      *://*/*
// @run-at       document-start
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Inject directly into the Main World so we actually intercept the page's alerts
    const payload = `(function() {
        try {
            // Keep a private, hidden reference to the original alert
            const originalAlert = window.alert;

            // Override the page's alert function to do absolutely nothing
            window.alert = function() {};

            // Restore the original alert after 5 seconds
            setTimeout(() => {
                window.alert = originalAlert;
            }, 5000);
        } catch (e) {}
    })();`;

    // Create the script tag
    const script = document.createElement('script');
    script.textContent = payload;

    // Inject instantly at document-start before the website's spam scripts run
    if (document.documentElement) {
        document.documentElement.appendChild(script);
        script.remove(); // Clean up the tag so the website doesn't know we are there
    }
})();