function js_is_number(in_item, sTemp)
  {         
   //alert(in_item);

    if(in_item!="")
    {
      if(isNaN(in_item))
      {
         sTemp = "Please enter a valid " + sTemp;	
     	 alert(sTemp);
		 return 0;
         //in_item.focus();
      }
	  else 
	  {
	  return 1;
	  }	 
    }
	else 
    {
	 sTemp = "Please enter a valid " + sTemp;	
	 alert(sTemp);
	 return 0;
	 }	
  }
  
function calc_bags()
    {
	var $a;
	$a = js_is_number(document.warmcel_form.Area.value,'area');
	//alert($a); 	
		
	if ($a > 0) 
	 {
	  var $b;
	  $b = js_is_number(document.warmcel_form.Thickness.value,'thickness');
	  //alert($b); 
	  if ($b > 0)
	  {
	   var $temp_var = Number(document.warmcel_form.Area.value) * ((Number(document.warmcel_form.Thickness.value)/1000)/0.2);
	   document.warmcel_form.bags.value = Math.ceil( Math.round($temp_var * 100) / 100 );
	  }
	 } 
	}