Export a website's cookies as JSON

copyCookies.js

window.confirm("Copy Cookies?") &&
  (() => {
    // modal (popup) div
    const div = document.createElement("div");
    div.setAttribute("style", "margin: auto; width: 25%; min-height: 25%; position: absolute; top: 25%; bottom: 25%; left: 25%; right: 25%; background-color: #ffe; padding: 1em; z-index:99999; border: 2px solid blue; border-radius: 1em; box-shadow: 4px 4px 8px #aaa;");

    // document.cookies keys and values as JSON text
    const cookiesJSONText = JSON.stringify(
      Object.fromEntries(
        document.cookie.split(/; ?/)
          .map(c => c.split("="))
      ), null, 2);

    // cookies as JS code that can be pasted into another browser
    const code = `Object.entries(${cookiesJSONText}).forEach(([k,v])=>{document.cookie=k + '=' + v;});`;

    const label = document.createElement("label");
    label.setAttribute("for", "cookiesTA");
    label.innerText = "Cookies as JSON:"
    label.setAttribute("style", "display: block;")

    div.appendChild(label)

    // a textarea containing our cookies as JSON
    const el = document.createElement("textarea");
    el.setAttribute("id", "cookiesTA");
    el.value = cookiesJSONText;
    el.setAttribute("readonly", "");
    el.setAttribute("style", "height: 75%; margin: 1em; display: block;")
    div.appendChild(el);

    const btnStyle = "padding: 0.5em; border: 1px solid #999; border-radius: 1em; display: inline-block; margin: 0.5em;";

    // "copy json" button
    const btn = document.createElement("button");
    btn.setAttribute("style", btnStyle);
    btn.innerText = "Copy JSON";
    btn.addEventListener("click", () => {
      el.select();
      document.execCommand("copy");
      document.body.removeChild(div);
      alert("Cookies Copied!");
    })
    div.appendChild(btn);

    // "copy code" button
    const btnCode = document.createElement("button");
    btnCode.setAttribute("style", btnStyle);
    btnCode.innerText = "Copy Code";
    btnCode.addEventListener("click", () => {
      el.value = code;
      el.select();
      document.execCommand("copy");
      document.body.removeChild(div);
      alert("Code Copied!\n\nYou can paste it into the developer tools of another browser e.g. firefox => chrome.");
    })
    div.appendChild(btnCode);

    // "cancel" button
    const btnCancel = document.createElement("button");
    btnCancel.setAttribute("style", btnStyle);
    btnCancel.innerText = "Cancel";
    btnCancel.addEventListener("click", () => {
      document.body.removeChild(div);
    })
    div.appendChild(btnCancel);

    document.body.append(div);

  })()