code: @Nonnull
    public PDFObjectOptions setPage (@Nullable final String sPage)
    {
      m_aPage = sPage == null ? null : JSExpr.lit (sPage);
      return this;
    }
docs: Alias for PDF Open Parameters "page" option. Any number entered here will
  cause the PDF be opened to the specified page number (if the browser
  supports it). If left unspecified, the PDF will open on page 1.
  
  @param sPage
  Page number
  @return this for chaining