function show_select()
 {
   
   if (document.getElementById('f_direction').value == 'from_kazan')
   {
   document.getElementById('f_to2').className= 'text hidden';
   document.getElementById('f_to').className= 'text visible';
   var tk = 0; 
   }
   if (document.getElementById('f_direction').value == 'to_kazan')
   {
   document.getElementById('f_to').className= 'text hidden';
   document.getElementById('f_to2').className= 'text visible';
   var tk = 1;
   }
 }
 
 function calculate_total()
 {
   var ttl = 0;
   var len = document.forms['calc']['length'].value;
   var len2 = document.forms['calc']['length2'].value;
   var thick = document.forms['calc']['frame'].value;
   if (len == 0)
   {
      if (len2 == 0)
	  {
		  document.getElementById('total').value='';
    	  return;
	  }
   }
   if (thick == 0)
   {
      document.getElementById('total').value='';
      return;
   }
   
   if (document.getElementById('f_direction').value == 'from_kazan')
   {
   ttl = (len * thick);
   } 
   else
   {
   ttl = (len2 * thick);
   }
   document.getElementById('total').value = Math.ceil(ttl/1000) + "000" + " ð.";
 }