//returns a two-digit string representing
//  the chapter and page number currently
//  loaded in the browser

function getCurrentChapterPage()
  {
  var iChapterPage = '0';
  var iChapterPos = gsURL.indexOf('/chapter_');
  
  if(iChapterPos != -1)
    {
    iChapterPage = gsURL.charAt(iChapterPos + 9) + gsURL.charAt(iChapterPos + 11);
    iChapterPage = iChapterPage.toString();
    }
    
  return iChapterPage;
  }