Attach (recommended) or Link to PDF file here:  [test.pdf](https://akmer.aikucun.com/a94a8fe5ccb19ba61c4c0873d391e987982fbbd3_1616477914120_83.pdf)


Configuration:
- Web browser and its version: chrome 87.0.4280.88
- Operating system and its version: windows10
- PDF.js version: 2.6.347
- Is a browser extension:

Steps to reproduce the problem:
1. just open 

What is the expected behavior? (add screenshot)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/17724610/112087066-473f8f80-8bc8-11eb-8efb-56139ec42a9c.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

if (isStream(js)) {
        js = bytesToString(js.getBytes());
      } else if (!isString(js)) {
        return;
      }
      if (javaScript === null) {
        javaScript = Object.create(null);
      }
      javaScript[name] = stringToPDFString(js);
    }
    if (obj && obj.has("JavaScript")) {
      const nameTree = new NameTree(obj.getRaw("JavaScript"), this.xref);
      const names = nameTree.getAll();
      for (const name in names) {
        
        
        const jsDict = names[name];
        if (isDict(jsDict)) {
          appendIfJavaScriptDict(name, jsDict);
        }
      }
    }
    
    const openAction = this._catDict.get("OpenAction");
    if (isDict(openAction) && isName(openAction.get("S"), "JavaScript")) {
      appendIfJavaScriptDict("OpenAction", openAction);
    }
    return javaScript;
  }
  get javaScript() {