con jquery

Codice PHP:

<html>
    <head>
        <script type='text/javascript' src='jq.js'></script>
        <script type='text/javascript' src='jqui.js'></script>
        <script type='text/javascript'>
            $(document).ready(
                function(){
                    $("input[type=checkbox]").click(
                        function(){
                            var conta = 0;
                            $("tr:last td:not(:first)").each(
                                function(){
                                    conta++;
                                    var somma=0;
                                    $("tr:not(:last)").each(
                                        function(){
                                            if($(this).children().children().first().is(":checked")){
                                                somma += parseInt($(this).children(':eq('+conta+')').attr("innerHTML"));
                                            }
                                        }
                                    )
                                    $(this).attr("innerHTML", somma);
                                }
                            )
                        }
                    )
                }
            )
        </script>
    </head>
    <body>
        <Table>
            <tr>
                <td>
                <input type='checkbox' name='riga1'  />
                </td>
                <td>1</td>
                <td>2</td>
                <td>1</td>
                <td>4</td>
                <td>1</td>
                <td>8</td>
                <td>1</td>
                <td>9</td>
                <td>-1</td>
                <td>12</td>
            </tr>
            
            
            <tr>
                <td>
                <input type='checkbox' name='riga2'/>
                </td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
            </tr>
            
            
            
            <tr>
                <td>
                <input type='checkbox' name='riga3'/>
                </td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
            </tr>
            
            
            
            
            
            <tr>
                <td>
                <input type='checkbox' name='riga4'/>
                </td>
                <td>1</td>
                <td>1</td>
                <td>13</td>
                <td>1</td>
                <td>1</td>
                <td>5</td>
                <td>1</td>
                <td>1</td>
                <td>2</td>
                <td>1</td>
            </tr>
            
            
            
            
            
            <tr>
                <td>
                <input type='checkbox' name='riga5'/>
                </td>
                <td>1</td>
                <td>1</td>
                <td>8</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>0</td>
                <td>1</td>
                <td>0</td>
            </tr>
            
            
            <tr class='risultato'>
                <td>
                TOTALE
                </td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
                <td>0</td>
            </tr>
            
        
        </table>

    </body>
</html> 
la somma viene fatta al click su una delle checkbox, quindi funziona se all'inizio nessuna checkbox è flaggata, tuttavia guardando il codice troverai facilemente la soluzione anche a questo