function isNumeric(strString)
   //  check for valid numeric strings 
   {
   var strValidChars = "0123456789.-";
   var strChar;
   var blnResult = true;
   var i=0;

   if (strString.length == 0) return false;

   //  test strString consists of valid characters listed above
   for (i = 0; i < strString.length && blnResult == true; i++)
      {
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1)
         {
         blnResult = false;
         }
      }
   return blnResult;
   }

  function openSubmenu(smName,imgNum){
    document.getElementById("shiureiTora_Div").style.display="none";
    document.getElementById("mosdot_Div").style.display="none";
  
    if (smName!=""){
      document.getElementById(smName).style.display="block";
    }
    
    for (i=1;i<11;i++){
			document.getElementById("menu_" + i).src="\/pics\/menu"+i+".jpg";
		}
		
		document.getElementById("menu_" + imgNum).src="\/pics\/menu"+imgNum+"R.jpg";
		if (currentPage>0){
			document.getElementById("menu_" + currentPage).src="\/pics\/menu"+currentPage+"c.jpg";
		}
  }