function showBookPg()
  {
   if (document.formElem.BookPgYes.checked)
  	{
  	document.getElementById("visibleBookPg").style.visibility = "visible";
	document.formElem.BookPgYes.focus()
  	}
   else
  	{
  	document.getElementById("visibleBookPg").style.visibility = "hidden";
  	}
  }