text: if (typeof Proxy === "undefined") {
      importScripts("https://cdn.jsdelivr.net/npm/proxy-polyfill@0.3/proxy.min.js");
  }
  importScripts("https://cdn.jsdelivr.net/npm/comlinkjs@3/umd/comlink.js");
  importScripts("../../build/schematron-browser.js");
  