Amazon_Keepa_Sakura_Button

Add links to Keepa and Sakura Checker to the Amazon.co.jp product screen.

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 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            Amazon_Keepa_Sakura_Button
// @name:ja         Amazonの商品画面に価格履歴とサクラチェックのボタンを追加
// @namespace       https://greasyfork.org/users/1324207
// @match           https://www.amazon.co.jp/dp/*
// @match           https://www.amazon.co.jp/*/dp/*
// @match           https://www.amazon.co.jp/gp/product/*
// @match           https://www.amazon.co.jp/exec/obidos/ASIN/*
// @match           https://www.amazon.co.jp/o/ASIN/*
// @match           https://www.amazon.co.jp/gp/aw/d/*
// @version         1.3.2
// @author          Lark8037
// @description     Add links to Keepa and Sakura Checker to the Amazon.co.jp product screen.
// @description:ja  Amazonの商品画面にKeepaとサクラチェッカーへのリンクを追加します。
// @license         MIT
// @icon            https://www.amazon.co.jp/favicon.ico
// ==/UserScript==

(function () {
    'use strict';

    const SELECTORS = ['#buyNow', '#add-to-cart-button', '#buybox .a-button-stack', '#add-to-cart-button-ubb', '#buybox-see-all-buying-choices', '#buybox-see-all-buying-choices-announce', '#rcx-subscribe-submit-button-announce', '#dealsAccordionRow', '#outOfStock'];

    if (!document.getElementById('checker-style')) {
        const s = document.createElement('style');
        s.id = 'checker-style';
        s.textContent = `.checker a{display:inline-block;border:0;height:4ex;line-height:4ex;margin-bottom:1.2ex;width:100%;text-align:center;color:black;border-radius:10em;text-decoration:none;font-size:1em}.sakura-checker-link{background:deeppink}.sakura-checker-link:hover{background:crimson}.price-history-link{background:deepskyblue}.price-history-link:hover{background:dodgerblue}@media screen and (max-width:768px){.checker a{height:5.5ex;line-height:5.5ex}}`;
        document.head.appendChild(s);
    }

    let lastASIN = '';
    const getASIN = () => {
        const m = location.pathname.match(/\/([A-Z0-9]{10})(?:[/?]|$)/);
        if (m) return m[1];
        const p = new URLSearchParams(location.search);
        return p.get('asin') || document.querySelector('[name="ASIN"], [name="ASIN.0"]')?.value || '';
    };

    const insertLinks = () => {
        const asin = getASIN();
        if (!asin || asin === lastASIN || document.getElementById('checker-links')) return;
        lastASIN = asin;

        let target;
        for (const sel of SELECTORS) {
            const el = document.querySelector(sel);
            if (el) {
                target = el.closest('div.a-section') || el.parentElement;
                break;
            }
        }
        if (!target) return;

        const c = document.createElement('div');
        c.id = 'checker-links';
        c.className = 'checker';

        for (const [href, text, cls] of [
            [`https://keepa.com/#!product/5-${asin}`, '価格履歴', 'price-history-link'],
            [`https://sakura-checker.jp/search/${asin}/`, 'サクラチェック', 'sakura-checker-link']
        ]) {
            const a = document.createElement('a');
            a.href = href;
            a.textContent = text;
            a.className = cls;
            a.target = '_blank';
            a.rel = 'noopener noreferrer';
            c.appendChild(a);
        }
        target.after(c);
    };

    new MutationObserver(insertLinks).observe(document.body, { childList: true, subtree: true });
    insertLinks();
})();