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specified in the [commit comment](https://github.com/mozilla/pdf.js/commit/8de98079ca05f8f7001ee077771055a57dc0e948) is outdated.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There are probably other problems with that code due to the outdated spec @calixteman was apparently working on.
break;
          case "println":
            console.log(value);
            break;
          case "zoom":
            this.pdfViewer.currentScaleValue = value;
            break;
        }
        return;
      }
      const element = document.getElementById(id);
      if (element) {
        element.dispatchEvent(new CustomEvent("updatefromsandbox", { detail }));
      } else {
        if (value !== undefined && value !== null) {
          
          pdfDocument.annotationStorage.setValue(id, value);
        }
      }
    };
    internalEvents.set("updatefromsandbox", updateFromSandbox);
    const visitedPages = new Map();
    const pageOpen = ({ pageNumber }) => {
      visitedPages.set(
        pageNumber,
        (async () => {
          
          
          let actions = null;
          if (!visitedPages.has(pageNumber)) {