Tampermonkey userscript for Advent of Code that prevents you from submitting non-numbers by accident and losing 1 minute to a misclick

AocGuardrails.user.js

// ==UserScript==
// @name         AoC Guardrails
// @namespace    https://masflam.com
// @version      2024-12-03
// @description  Prevent sending non-numbers by accident.
// @author       MasFlam
// @match        *://adventofcode.com/*
// @icon         https://adventofcode.com/favicon.png
// @grant        none
// ==/UserScript==

(function() {
    const style = document.createElement('style');
    style.type = 'text/css';
    //style.styleSheet.cssText = ':invalid { border-color: red; }';
    style.appendChild(document.createTextNode(':invalid { border-color: red !important; }'));
    document.getElementsByTagName('head')[0].appendChild(style);

    console.log(document.getElementsByName('answer'));
    const ans_inputs = document.getElementsByName('answer');
    for (const answer_input of ans_inputs) {
        console.log(answer_input);
        answer_input.required = true;
        const ins = document.createElement('label');
        //ins.style = 'color: red;';
        const L = document.createElement('span');
        const R = document.createElement('span');
        L.innerText = ' ';
        R.innerText = 'force?';
        const checkbox = document.createElement('input');
        checkbox.type = 'checkbox';
        checkbox.addEventListener('change', (evt) => {
            console.log(evt.target.checked);
            if (!evt.target.checked) {
                for (const ansin of ans_inputs) {
                    console.log(ansin);
                    ansin.pattern = '[0-9]+';
                }
            } else {
                for (const ansin of ans_inputs) {
                    console.log(ansin);
                    //ansin.removeAttribute('pattern');
                    ansin.pattern = '.+';
                }
            }
        });
        checkbox.dispatchEvent(new Event('change'));
        ins.appendChild(L);
        ins.appendChild(checkbox);
        ins.appendChild(R);
        answer_input.insertAdjacentElement('afterend', ins);
    }
})();