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specified in the [commit comment](https://github.com/mozilla/pdf.js/commit/8de98079ca05f8f7001ee077771055a57dc0e948) is outdated.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There are probably other problems with that code due to the outdated spec @calixteman was apparently working on.
eventBus._off("zoomin", webViewerZoomIn);
    eventBus._off("zoomout", webViewerZoomOut);
    eventBus._off("zoomreset", webViewerZoomReset);
    eventBus._off("pagenumberchanged", webViewerPageNumberChanged);
    eventBus._off("scalechanged", webViewerScaleChanged);
    eventBus._off("rotatecw", webViewerRotateCw);
    eventBus._off("rotateccw", webViewerRotateCcw);
    eventBus._off("optionalcontentconfig", webViewerOptionalContentConfig);
    eventBus._off("switchscrollmode", webViewerSwitchScrollMode);
    eventBus._off("scrollmodechanged", webViewerScrollModeChanged);
    eventBus._off("switchspreadmode", webViewerSwitchSpreadMode);
    eventBus._off("spreadmodechanged", webViewerSpreadModeChanged);
    eventBus._off("documentproperties", webViewerDocumentProperties);
    eventBus._off("find", webViewerFind);
    eventBus._off("findfromurlhash", webViewerFindFromUrlHash);
    eventBus._off("updatefindmatchescount", webViewerUpdateFindMatchesCount);
    eventBus._off("updatefindcontrolstate", webViewerUpdateFindControlState);
    if (_boundEvents.reportPageStatsPDFBug) {
      eventBus._off("pagerendered", _boundEvents.reportPageStatsPDFBug);
      eventBus._off("pagechanging", _boundEvents.reportPageStatsPDFBug);
      _boundEvents.reportPageStatsPDFBug = null;
    }
    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
      eventBus._off("fileinputchange", webViewerFileInputChange);
      eventBus._off("openfile", webViewerOpenFile);
    }
    _boundEvents.beforePrint = null;
    _boundEvents.afterPrint = null;
  },
  unbindWindowEvents() {