function check_total_count()
{
  var sel = document.getElementById("ddl_ppo");
  var ppo = sel.options[sel.selectedIndex].value;
  
  sel = document.getElementById("ddl_ppf");
  var ppf = sel.options[sel.selectedIndex].value;
  
  sel = document.getElementById("ddl_paname");
  var paname = sel.options[sel.selectedIndex].value;
  
  if ((ppo == '全選') &&
      ((ppf == '全選') || (ppf == '看板論文')) &&
      (paname == '全選'))
  {
    return confirm('您查詢的論文總數超過 500 篇，\n需要較長時間處理，\n要繼續嗎？');
  } 
  else
  {
    return true;
  }
}