niente da fare. questo il sorgente:
codice:
<script type="text/javascript" src="js/jquery-1.6.2.min.js"></script>
<script type="text/javascript" src="js/jquery.calculation.min.js"></script>
<script type="text/javascript">
  var bIsFirebugReady = (!!window.console && !!window.console.log);
  $("[id^=total_item]").calc(
  // the equation to use for the calculation
  "qty * price",
  // define the variables used in the equation, these can be a jQuery object
  {
    qty: $("input[name^=qty_item_]"),
    price: $("[id^=price_item_]")
  },
  // define the formatting callback, the results of the calculation are passed to this function
  function (s){
    // return the number as a dollar amount
    return "$" + s.toFixed(2);
  },
  // define the finish callback, this runs after the calculation has been complete
  function ($this){
    // sum the total of the $("[id^=total_item]") selector
    var sum = $this.sum();
    
    $("#grandTotal").text(
      // round the results to 2 digits
      "$" + sum.toFixed(2)
    );
  }
);
</script>

<script>
  document.createElement('article');
  document.createElement('section');
  document.createElement('hgroup');
  document.createElement('header');
  document.createElement('footer');
</script>
</head>

<body>
<table class="sortable" width="100%">
  <thead>
  <tr>
    <th scope="col">Prodotto</th>
    <th scope="col">Quantita</th>
    <th scope="col">Prezzo</th>
    <th scope="col">Totale &euro;</th>
  </tr>
  </thead>

  <tbody>
<tr><td>Prodotto A</td><td><input type="text" value="1" name="qty_item_1" id="qty_item_1" size="3"></td><td id="price_item_1">43.5</td><td id="total_item_1">43.5</td></tr>
<tr><td>Prodotto B</td><td><input type="text" value="1" name="qty_item_2" id="qty_item_2" size="3"></td><td id="price_item_2">43.5</td><td id="total_item_2">43.5</td></tr>
<tr><td>Prodotto C</td><td><input type="text" value="1" name="qty_item_3" id="qty_item_3" size="3"></td><td id="price_item_3">43.5</td><td id="total_item_3">43.5</td></tr>
<tr><td>Prodotto D</td><td><input type="text" value="1" name="qty_item_4" id="qty_item_4" size="3"></td><td id="price_item_4">43.5</td><td id="total_item_4">43.5</td></tr>
<tr><td colspan="3">TOTALE</td><td style="text-align: right" id="grandTotal">0,00</td>
  </tbody>
</table>