Don't get me wrong, it's great that @calixteman wanted to implement that — JS should definitely be supported! I don't want to come off as rude or attacking.

For starters, JS reference specified in the [commit comment](https://github.com/mozilla/pdf.js/commit/8de98079ca05f8f7001ee077771055a57dc0e948) is outdated. It's version 8.1 from 2007… We're more than decade past that now. We should be implementing [Acrobat DC SDK](https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/AcrobatDC_js_api_reference.pdf) ([here](https://help.adobe.com/en_US/acrobat/acrobat_dc_sdk/2015/HTMLHelp/#t=Acro12_MasterBook%2FJS_API_AcroJS%2FJavaScript_API.htm) in a nice HTML version).

Other than that, the Doc object now is only implemented with `info` property with standard fields (`Title`, `Author`, `Subject`, `Keywords`, `Creator`, `Producer`, `CreationDate`, `ModDate` and `Trapped`, case insensitive). But [according to the spec](https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/AcrobatDC_js_api_reference.pdf#page=243) (even [in that old version](https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/js_api_reference.pdf#page=243)), this object can contain other, non-standard properties, that can be set both in Acrobat interface and in JS (which are case-sensitive then).

Acrobat 9.0 introduced another field to that property, `Authors`, containing semicolon-delimited list of authors.

There are probably other problems with that code due to the outdated spec @calixteman was apparently working on.
if (!PDFViewerApplication.supportsFullscreen) {
    appConfig.toolbar.presentationModeButton.classList.add("hidden");
    appConfig.secondaryToolbar.presentationModeButton.classList.add("hidden");
  }
  if (PDFViewerApplication.supportsIntegratedFind) {
    appConfig.toolbar.viewFind.classList.add("hidden");
  }
  appConfig.mainContainer.addEventListener(
    "transitionend",
    function (evt) {
      if (evt.target ===  this) {
        PDFViewerApplication.eventBus.dispatch("resize", { source: this });
      }
    },
    true
  );
  try {
    webViewerOpenFileViaURL(file);
  } catch (reason) {
    PDFViewerApplication.l10n
      .get("loading_error", null, "An error occurred while loading the PDF.")
      .then(msg => {
        PDFViewerApplication.error(msg, reason);
      });
  }
}
let webViewerOpenFileViaURL;
if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
  webViewerOpenFileViaURL = function (file) {
    if (file && file.lastIndexOf("file:", 0) === 0) {