[okapo]

Помогите создать калькулятор

var tva = 5;
var intop = 2;
var redp = 3;
$('#setprice').onkeyup(function() {
    var plan = $('input:text[name=plan]').val();
  var timer = $('input:text[name=time]').val();
  var top = $('input:text[name=top]').val();
  var locat = $('input:text[name=locat]').val();
  if(timer == 20) tprice = t20;
  else if(timer == 20) tprice = t30;
  else if(timer == 20) tprice = t40;
  else if(timer == 20) tprice = t50;
  else if(timer == 20) tprice = t60;
  else tprice = t20;
  summa = plan + (tprice * (1 + tva / 100));
  
  if (top==1) summa = summa + intop;
    if (locat==1) summa = summa + redp;
    $('#summa').html(summa);
});

вот html

<input type="text" name="plan" maxlength="7" id="setprice" />

<select name="time" id="setprice">
         <option value="20">20 sec&nbsp;({serf_20} {valuta})</option>
         <option value="30">30 sec&nbsp;({serf_30} {valuta})</option>
         <option value="40">40 sec&nbsp;({serf_40} {valuta})</option>
         <option value="50">50 sec&nbsp;({serf_50} {valuta})</option>
         <option value="60">60 sec&nbsp;({serf_60} {valuta})</option>
</select>

<select name="top" id="setprice">
      <option value="1">Да (+ {serf_top} {valuta})</option>
      <option value="0" selected="">Нет</option>
</select>

<select name="locat" id="setprice">
      <option value="1">Да (+ {serf_loc} {valuta})</option>
      <option value="0" selected="">Нет</option>
</select>

// вывод суммы 
<span id="summa">0</span>