function myprefix_edit_user_cb(){
    $user_id=$_REQUEST['user_id'];

    $user = get_user_by( 'ID', $user_id );

        echo
            '   <fieldset>
                <legend>Form</legend>
                <form id="update-form" action="" method="POST">
                    <label>Username:<span style="color:red">*</span></label>

                    <input name="id" type="hidden" value=" '. $user->ID.' " required>
                    <input name="username" type="text" value=" '. $user->user_login.' " required>
                    <label>Email:<span style="color:red">*</span></label>
                    <input name="email" type="email" value="'.$user->user_email.'" required>
                    <label>Password:</label>
                    <input name="password" type="password" value="">
                    <input class="btn btn-default" name="submit" type="submit" value="submit">
                </form>
                </fieldset>
            ';

        die();
    }

function update_data()
  {

    wp_enqueue_style('mysample');

    global $reg_errors;

    if(isset($_POST['submit']))
    {

        $username=isset($_POST['username'])?$_POST['username']:null;
        $email=isset($_POST['email'])?$_POST['email']:null;
        $password=isset($_POST['password'])?$_POST['password']:null;

        validation_for_edit($username,$email,$password);

        $userdata = array(

            'ID' => $_POST['id'],
            'user_login'    =>   $username,
            'user_email'    =>   $email,
            'user_pass'     =>   $password,
        );

        echo "<pre>";print_r($userdata);

        if(1 > count( $reg_errors->get_error_messages() ) )
        {
            if($userdata=wp_update_user( $userdata ))
            {
                    echo '<span id="message">Update complete.</span>';
                    echo 'Goto <a href="' . get_site_url() . '/wp-login.php">login page</a>';
            }
        }
    }
    die();
 }