<tr class="cart-order">
    <td align="left">тестовый товар 2</td>
    <td><b><span class="weight">30</span> кг.</b></td>
    <td><span class="price">5500</span> руб.</td>
    <td align="center">
        <input class="count" type="text" size="2" title="изменить количество" value="2">
    </td>
</tr>

var orders = $('tr.cart-order');
console.log(orders);

console.log(orders[0]);