User script used to update page contents

page-manipulation.user.js

// ==UserScript==
// @name         Page Manipulation
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Updates page contents
// @author       [email protected]
// @include      https://target.site/*
// @grant        none
// ==/UserScript==

let updater = setInterval(update, 1)
function update() {
    if (document.getElementById("LC1").children[2].innerHTML != "new-text"){
        document.getElementById("LC1").children[2].innerHTML = "new-text"
        // other edits
        clearInterval(updater)
    }
}