How do you target the select box for the table below and fire an onchange function...Thanks

How do you target the select box for the table below and fire an onchange function...Thanks

<div class="container">
    <div class="row">
        <div class="col-xs-12">
    <div class="invoice-title">
    <h2 id="me">Orders</h2><h3 class="pull-right">Order # 12345</h3>
    </div>
    <hr>
    <div class="row">
    <div class="col-xs-6">
    <address>
    <strong>Billed To:</strong><br>
     <input type="text" value="" placeholder='name' /><br>
    <input type="text" value="" placeholder='address' /><br>
    <input type="text" value="" placeholder='street' /><br>
    <input type="text" value="" placeholder='location' />
    </address>
    </div>
    <div class="col-xs-6 text-right">
    <address>
        <strong>Shipped To:</strong><br>
   
   
    </address>
    </div>
    </div>
    <div class="row">
    <div class="col-xs-6">
    <address>
    <strong>Payment Method</strong><br>
    <br>
   
    </address>
    </div>
    <div class="col-xs-6 text-right">
    <address>
    <strong>Order Date:</strong><br>
    4<br><br>
    </address>
    </div>
    </div>
    </div>
    </div>
 <div class="container">
    <div class="row clearfix">
    <div class="col-md-12 table-responsive">

<table class="table table-bordered table-hover table-sortable" id="tab_logic">
  <thead>
    <tr >
      <th class="text-center">
        Product
      </th>
      <th class="text-center">
        Quantity
      </th>
      <th class="text-center">
        Price
      </th>
        <th class="text-center">
        SubTotal
      </th>
          <th class="text-center" style="border-top: 1px solid #ffffff; border-right: 1px solid #ffffff;">
          Action
      </th>
    </tr>
  </thead>
  <tbody>

      <tr id='addr0' data-id="0" class="hidden">

          <td data-name="name">
            <form>
              
              <select name="sel0" id="selectbox" onchange="getprice()">
                   
                    <option value="" id="optionval">One Product</option>
<option value="" id="optionval">Two Product</option>
<option value="" id="optionval">Three Product</option>
                   
              </select>
            </form>

          </td>
          <td data-name="mail">

              <input type="text" value=""name='mail0' placeholder='quantity' class="form-control"/>
          </td>
          <td data-name="desc">
              <form>
                  <input type="text" id="item_price" value="0.0">
              </form>

          </td>

        <td data-name="sel">
            <input type="text" name='mail0' placeholder='total' class="form-control"/>
      </td>
      <td data-name="del">
          <button nam"del0" class='btn btn-danger glyphicon glyphicon-remove row-remove'></button>
      </td>


    </tr>

   
  </tbody>
</table>






      <a id="add_row" class="btn btn-default pull-right">Add Row</a>
</div>

</div>



</div>