Block any included website besides all other websites

JavaScript
1

I am trying to create a script to block any included website (included in an includes() test) besides all other website but it doesn’t work. Any ideas what I did wrong please?

// ==UserScript==
// @name         block_any_included_website_besides_all_other_websites
// @match        *://*/*
// @run-at       document-start

// ==/UserScript==
window.setTimeout ( ()=>{
if (window.location.href.includes('wikipedia.org')) {
    window.open("https://example.com/", "_self");
    // window.location.replace("https://example.com");
    // window.location.href("https://example.com");
}
}, 100);
2

Reinventing the wheel?
(Install something like the Redirector extension. Let someone else do the coding.)

Does the code actually get to the stage of trying to execute window.open?

3

If testing if it reaches that stage is done with the “Network” tab in the dev tool than I got to say - I don’t know how to work with this tab, the interface there confuses me.

Otherwise I’d ask, why wouldn’t it reach that stage? I mean, I recall to also try document-idle and document-end and when combining these with a setInterval() that pretty much should cover all stages, should it not?

I have also tried a self executing function which I understand to reflect document-start and listening to the load event which I understand to reflect a document-idle situation and if I am not mistaken, everything works in console but not in a user script.