当我单击一个按钮时，它没有通过ajax jquery将数据发送到changePassword.php

Question

This is the form through which I want to send data to changePassword.php. but it didn't send data.

<form class="form-horizontal" method="post">
    <div class="form-group">
        <label for="inputName" class="col-sm-2 control-label">Current Password</label>
        <div class="col-sm-10">
            <input type="text" class="form-control" id="current_password" name="current_password" placeholder="Name">
        </div>
    </div>
    <div class="form-group">
        <label for="inputEmail" class="col-sm-2 control-label">New Password</label>
        <div class="col-sm-10">
            <input type="password" class="form-control" id="new_password" name="new_password" placeholder="Email">
        </div>
    </div>
    <div class="form-group">
        <label for="inputEmail" class="col-sm-2 control-label">Confirm Password</label>
        <div class="col-sm-10">
            <input type="password" class="form-control" id="confirm_password" name="confirm_password" placeholder="Email">
        </div>
    </div>
    <div class="form-group">
        <div class="col-sm-offset-2 col-sm-10">
            <button type="submit" name="changePassword" id="changePassword"  class="btn btn-primary">Change Password</button><br><br><br><br><br>
        </div>
    </div>
</form>

This is the Ajax code through which the data is sent to changePassword.php .

$("#changePassword").click(function(event) {
     var old_pass = $('#current_password').val();
     var new_pass =  $('#new_password').val();
     var conf_pass = $('#confirm_password').val();

     $.ajax({
          url: "ajax/changePassword.php",
          type: "post",
          data: ({ old_pass: old_pass, new_pass: new_pass, conf_pass: conf_pass}),
          success: function(data){

          }
     });
});

And this is the changePassword.php page.

 <?php
    session_start();
    include"../include/connection.php";

     if (!isset($_SESSION['FT_id']))
            {

            }

    $single_user=$_SESSION['FT_id'];
    $query="select * from faculty where faculty_phone=$single_user";
    $cm=sqlsrv_query($conn,$query);
    $resultFT = sqlsrv_fetch_array($cm);        

           echo $password = $_POST['old_pass']; exit;    

    ?>