Reference a hidden value in a form using jQuery/JavaScript - php

Question

I am new to web development
I have PHP delete function that I want to use to delete rows from a database table.
if($form_no==="delete" && isset($_POST['id']) && isset($_POST['form_no']))
{
switch ($_POST['form_no']) {
case 1:$table="employees"; break;
default:break;
}
$query="DELETE from ".$table." where id=".$_POST['id'];
mysql_query($query)or die( ' '.mysql_error().' '.$query);
$message='deleted';
switch ($_POST['form_no']) {
case 1:manageEmployees($message);break;
default:break;
}
}
here is one of the forms that I am displaying on screen
<tr><th>First Name</th><th>Last Name</th><th>Email</th><th>Password</th><th>Phone number</th></tr>
<tr><td><input type="hidden" id="form_no" name="form_no" value="1"></td></tr>
<tr><td><input type="text" name="firstname[]" id="firstname"></td>
<td><input type="text" name="lastname[]" id="lastname"></td>
<td><input type="text" name="email[]" id="email"></td>
<td><input type="text" name="password[]" id="password"></td>
<td><input type="text" name="phone_no[]" id="phone_no"></td>
<td><button type="submit" name="submit" id="submit">Add Employee</button></td>
<td><button type="button" name="delete" class="delete" value=21>Delete Employee</button></td></tr>
<td><p><p></td>
</tr>
I am trying to get access to other values in a form. When the button is clicked I can get the ID I am looking for as it is the value of the button. What I really want to do is get the value of the hidden field and find out in which for the delete button is pressed.
I can not use find elementById as the delete buttons are not unique nor are the forms. I am trying to use $(this).parents().parents('#form_no').val(), however this returns undefined.
I know that it must be possible to do but I am not getting any closer, many thanks in advance if any one can point me in the right direction.