<table border="1">
  <tr>
   <th>Name</th>
   <th>Part</th>
   <th>Due Date</th>
   <th>New Due Date</th>
   <th>Save</th>
  </tr>
  <?php foreach($due_dates as $date):?>
   <tr>
    <td><?php echo $date['name'];?></td>
    <td><?php echo $date['part'];?></td>
    <td><?php echo $date['date_deadline'];?></td>
   <form action="<?php echo site_url('application_deadlines/update_due_date');?>" name="new_form" method="POST">
    <td>
     <input type="hidden" name="name" value="<?php echo $date['name']; ?>" >
     <input type="hidden" name="part" value="<?php echo $date['part']; ?>" >
     <input type="text" class="text date_input date_picker date" name="new_due" autocomplete="off" name="date"; />
    </td>
    <td><button class="submit">Save</button>
    </td>
   </form>
  </tr>
  <?php endforeach;?>

 </table>

$('.submit').click(function(e){
  e.preventDefault();
  // var new_due_date = document.getElementsByName("date");
  var new_due_date = $(this).parent().prev().find('.date').val();
  if(confirm("New due date is\n" +new_due_date+ "\n \n Do you want to save it?")){
   //how to call update database function here?
   //document.getElementsById("new_form").submit();
 //  $('.new_form').submit();
   alert("Change Saved");
  }
  else{
   alert("Save Canceled");
  }
 });