Greasy Fork is available in English.

AtCoder Registration Autofill

AtCoderの参加登録情報を保存し、自動入力します。

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

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

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

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

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

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

(I already have a user script manager, let me install it!)

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.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         AtCoder Registration Autofill
// @namespace    https://github.com/Raclamusi
// @version      1.0.0
// @description  AtCoderの参加登録情報を保存し、自動入力します。
// @author       Raclamusi
// @supportURL   https://github.com/Raclamusi/atcoder-registration-autofill
// @match        https://atcoder.jp/contests/*/register
// @grant        none
// @license      CC0
// ==/UserScript==

(function() {
    "use strict";

    const storageKey = "atcoder_registration_autofill__data";
    const getAutofillData = () => {
        return JSON.parse(localStorage.getItem(storageKey));
    };
    const setAutofillData = (name, type, value) => {
        const data = getAutofillData() ?? {};
        if (!(name in data)) {
            data[name] = {};
        }
        if (type === "radio") {
            if (!(type in data[name])) {
                data[name][type] = [];
            }
            data[name][type].unshift(value);
        }
        else {
            data[name][type] = value;
        }
        localStorage.setItem(storageKey, JSON.stringify(data));
    };

    const form = document.querySelector(".form-horizontal");
    if (getAutofillData() === null) {
        setAutofillData("日本国内在住か?", "radio", "Yes");
    }
    for (const [name, values] of Object.entries(getAutofillData())) {
        const input = form[name];
        if (input) {
            const type = (input instanceof RadioNodeList) ? "radio" : input.type;
            if (type in values) {
                const value = values[type];
                if (type === "radio") {
                    const radioButtons = [...input].map(e => e.value);
                    for (const v of value) {
                        if (radioButtons.includes(v)) {
                            input.value = v;
                            break;
                        }
                    }
                }
                else if (type === "checkbox") {
                    input.checked = value;
                }
                else {
                    input.value = value;
                }
            }
        }
    }

    for (const input of form) {
        if (input.type === "checkbox") {
            input.addEventListener("change", e => {
                setAutofillData(e.target.name, e.target.type, e.target.checked);
            });
        }
        else {
            input.addEventListener("change", e => {
                setAutofillData(e.target.name, e.target.type, e.target.value);
            });
        }
    }
})();