Enable the download of simple applets to jnlp format

downloadAppletAsJnlp.js

// ==UserScript==
// @name         Convert applet to downloadable jnlp
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        http://192.168.1.23/kvms.html
// @icon         https://www.google.com/s2/favicons?sz=64&domain=1.23
// @grant        none
// @require      https://cdnjs.cloudflare.com/ajax/libs/handlebars.js/4.7.7/handlebars.js
// ==/UserScript==

(function() {
    'use strict';
    const template = `<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="1.0+" codebase="{{ codebase }}" href="">
    <information>
        <title>Launch applet with Web Start</title>
        <vendor>Foo Bar Inc.</vendor>
        <offline-allowed/>
    </information>
    <resources>
        <jar href="{{ jarHref }}" main="true" />
    </resources>
    <applet-desc main-class="{{ mainClass }}" width="300" height="200" name="egal">
    {{#each params}}
      <param name="{{ name }}" value="{{ value }}"/>
    {{/each}}
    </applet-desc>
  <security>
    <all-permissions />
  </security>
  <update check="background"/>
</jnlp>
`;
    const applets = document.querySelectorAll('applet');

    const downloadAsJnlp = (applet) => {
        const data = {
            codebase: new URL("./", document.baseURI).toString(),
            mainClass: applet.attributes.code.textContent,
            jarHref: applet.attributes.archive.textContent,
            params: parseParams(applet),
        };
        const render = Handlebars.compile(template);
        const blob = new Blob([render(data)], {type: "octet/stream"});
        const href = window.URL.createObjectURL(blob);
        const name = 'applet.jnlp';
        return {href, name};
    }

    const parseParams = (applet) => {
        return Array.from(applet.querySelectorAll('param')).map(parseParam);
    }
    const parseParam = (param) => {
        return {
            name: param.name,
            value: param.value,
        }
    }

    const createDownloadLinks = (applets) => {
        const count = applets.length;
        console.log(`Found ${count} applets`);
        for (let i = 0; i < count; i++) {
            createDownloadLink(applets[i]);
        }
    }

    const createDownloadLink = (applet) => {
        const downloadLink = document.createElement('a');
        const {href, name} = downloadAsJnlp(applet);
        downloadLink.href = href;
        downloadLink.download = name;
        downloadLink.appendChild(document.createTextNode("Download as jnlp"));
        applet.prepend(downloadLink);
    }

    createDownloadLinks(applets);
})();