Submitting form via POST with jQuery and Ajax - php

Question

I am trying to POST data from a form using jQuery & Ajax. However, when I check on my PHP to see if the form has been "submitted", it shows it has not because the MySQL code does not run. I am guessing my HTML is not setup correctly and therefore the Ajax request is not sending the data to my post-update.php script. Here is my code:
<script type="text/javascript">
$(document).ready(function() {
$('#ajax-remove-completion-date').click(function() {
$.ajax({
type:'POST',
url:'post-update.php',
data: dataString,
success: function(response) {
$('#success-remove-completion-date').removeClass('hidden');
}
});
});
});
HTML:
<form action="">
<div id="myModal1" class="modal hide fade" tabindex="-1" role="dialog" aria-labelledby="myModalLabel1" aria-hidden="true">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true"></button>
<h3 id="myModalLabel3">Remove Completion Date</h3>
</div>
<div class="modal-body">
<p>Are you sure you want to remove the students Completion Date?</p>
</div>
<div class="modal-footer">
<button class="btn" data-dismiss="modal" aria-hidden="true">Close</button>
<button class="btn blue" data-dismiss="modal" id="ajax-remove-completion-date">Yes</button>
<input type="hidden" name="submitted" value="remove-completion-date" />
</div>
</div>
</form>
PHP:
<?
session_id();
session_start();
require_once('assets/includes/mysql-connect.php');
/*Check to see if the completion date is being removed*/
if ($_POST['submitted'] == 'remove-completion-date') {
$query = "UPDATE students SET completion_date = NULL, completed = NULL WHERE student_id = {$_SESSION['student_id']} LIMIT 1";
$result = mysqli_query($dbc, $query);
}
?>

Answer 1

Where does dataString come from?
It's better if you define the data you want to send as an object. It's more readable and it's automatically converted to a query String.
$(document).ready(function() {
$('#ajax-remove-completion-date').click(function() {
$.ajax({
type:'POST',
url:'post-update.php',
data: {
submitted: 'remove-completion-date'
},
success: function(response) {
$('#success-remove-completion-date').removeClass('hidden');
}
});
});
});
If you want to take the value from the field, set submitted as:
$('input[name="submitted"]').val()