Find class in table row

Take a look at this table:

<table cellpadding="0" cellspacing="0" class="order_form">
    <tr>
        <th>Amount</th>
        <th>Desc</th>
        <th>Price</th>
        <th>To开发者_StackOverflow中文版tal</th>
    </tr>
    <tr>
        <td><input type="text" class="order_count" /></td>
        <td>
            <span class="order_desc">Middagstallerken</span>
        </td>
        <td>
            <span class="order_price">1,15</span>
        </td>
        <td>
            <span class="order_each_total"></span>
        </td>
    </tr>
    [...]
</table>

Upon entering amount I need to select the class "order_price" and multiply it with the value of the input "order_count" and place it in "order_each_count". I have a lot of these rows so I need to find the next class in the row.

I have tried using some function like this but without result:

<script type="text/javascript">
    $(document).ready(function(){
        $('.order_count').keyup(function() {
            var each_price = $(this).prevUntil("tr").find("span.order_price").text();
        });
     });
</script>

I hope someone have a good solution :-)

Use closest() instead of prevUntil:

$(document).ready(function(){
    $('.order_count').keyup(function() {
        var amount = parseInt($(this).val(), 10);
        var each_price = $(this)
                             .closest('tr')
                             .find('span.order_price')
                             .text()
                             .replace(',', '.'); // Floats use . as separator

        each_price  = parseFloat(each_price);
        total_price = amount * each_price;

        // Update the value
        $(this)
            .closest('tr')
            .find('span.order_each_total')
            .text(total_price
                .toFixed(2) // "Round" to two decimal places
                .replace('.', ',') // Format properly
            );
    });
 });

Remember to use parseFloat or parseInt when trying to use numbers from DOM in calculations – they're strings as default.