code: func (p *WebPage) InjectJS(filename string) error {
  	var resp struct {
  		ReturnValue bool `json:"returnValue"`
  	}
  	if err := p.ref.process.doJSON("POST", "/webpage/InjectJS", map[string]interface{}{"ref": p.ref.id, "filename": filename}, &resp); err != nil {
  		return err
  	}
  	if !resp.ReturnValue {
  		return ErrInjectionFailed
  	}
  	return nil
  }
docs: // InjectJS injects an external script from the local filesystem.
  //
  // The script will be loaded from the Process.Path() directory. If it cannot be
  // found then it is loaded from the library path.