如何在表格中添加另一行从下拉列表中选择一个选项？

Question

This is what my table looks like:

This is my code:

    <table class="inventory" style="float:left;">
  <tbody>
    <tr>
        <th>Date bought</th>
      <th>Item</th>
      <th>Quantity</th>
      <th>Total</th>
      </tr>

    <tr>
        <td>
             <link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css">
        <script src="//code.jquery.com/jquery-1.10.2.js"></script>
        <script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>
        <link rel="stylesheet" href="style.css">
        <script>
        $(document).ready(function() {
            $( "#datepicker" ).datepicker();
        });
        </script>
        <input type="text" id="datepicker"/>
        </td>
      <td>
          <select name="item_name_update" value="item_name_update" class="form-control ddplaceholder" style="width:220px; padding-left:40px;font-size:18px;font-family:Roboto;">
                   <option value="" disabled selected>Select Item</option>
            <?php
            $sth = $conn->prepare('Select item_name From item');
            $sth->execute();
            $data = $sth->fetchAll();   
            foreach ($data as $row ){
                if($row['item_name']!="")
             echo ' <option id=\"ItemName\" name=\"ItemName\" value="' .$row['item_name']. '">'.$row['item_name'].'</option>';
            }?>
            </select>
      </td>
      <td>
        <input type="text" placeholder="Quantity" name="Quantity" id="Quantity"/>
      </td>
      <td>
       <input type="text" placeholder="Total" value=""/>
      </td>
    </tr>
         <?php $totalCost="";
            if(!empty($_POST['item_name_update']) && !empty($_POST['datepicker']) && !empty($_POST['Quantity'])){
           $sth = $conn->prepare('Select price_per_unit From bill where item=:item and date=:date');
            $sth->execute(array(':item'=>$_POST['item_name_update'], ':date'=>$_POST['datepicker']));
            $data = $sth->fetchAll();   
            foreach ($data as $row ){
         $totalCost=($row['price_per_unit']*$_POST['Quantity']);
            }}
                ?>
  </tbody>
</table>

I want to add a row to the table each time an item is selected from the drop down. How do I do that? Is there a simple solution to it? Do I add a loop and add document.change in the select drop down?

Also, I want to add the total of all the Total textboxes that will be there.

EDIT:

I got some code below which adds new row. But new row should be added when I select a value from drop down of newest row. Right now it's adding on selecting the FIRST drop down ONLY.

Answer 1

Yes, we can do it using insertAfter method. You should call it on the change of the select tag by

$(function() {
   $("select").change(function() {
       $('<tr><td>new td1</td><td>new td2</td></tr>').insertAfter($(this).closest('tr'));
   });
});

Hope it helps :) Here is the Jsfiddle