inscriboor/extension/content.js

(() => {
  const script = document.createElement("script");
  script.src = chrome.runtime.getURL("injected.js");
  script.onload = () => script.remove();
  (document.documentElement || document.head).appendChild(script);

  let port;
  const connect = () => {
    port = chrome.runtime.connect({ name: "inscriboor-provider" });
    port.onMessage.addListener(message => window.postMessage({ source: "inscriboor-extension", ...message }, "*"));
    port.onDisconnect.addListener(() => { port = null; });
  };
  connect();

  window.addEventListener("message", event => {
    if (event.source !== window || event.data?.source !== "inscriboor-page") return;
    if (!port) connect();
    port.postMessage({ id:event.data.id, method:event.data.method, params:event.data.params, origin:location.origin });
  });
})();