Amazon - Open Channel Page from Offer Page.
// ==UserScript==
// @name Amazon - Open Channel Page from Offer Page
// @description Amazon - Open Channel Page from Offer Page.
// @version 0.1
// @author to
// @namespace https://github.com/to
// @license MIT
//
// @grant GM_registerMenuCommand
// @grant GM_openInTab
//
// @match https://www.amazon.co.jp/gp/video/offers/*
// @icon https://www.google.com/s2/favicons?sz=64&domain=amazon.co.jp
// ==/UserScript==
GM_registerMenuCommand('Open', () => {
let match = location.href.match(/benefitId=(.+?)(&|$)/);
if(match)
GM_openInTab('https://www.amazon.co.jp/gp/video/storefront/?contentType=subscription&contentId=' + match[1]);
});