Wordpress Widget图像上传到媒体库

Question

我正在尝试在Wordpress小部件中上传媒体。 我用Google搜索了一下，发现了这个：

http://www.paulund.co.uk/add-upload-media-library-widgets

以该教程为基础，我编写了以下内容（大部分内容，复制+粘贴）：

<?php 
error_reporting(E_ALL);
/*
Plugin Name: Dulkre Widgets
Plugin URI: http://www.dulkre.com.ar
Description: Widgets para los laterales del sitio dulkre.com.ar
Version: 1.0
Author: Pablo Bertran
Author URI: http://www.pablobertran.com
*/

class InfoProducto extends WP_Widget {

    function __construct(){
        $params = array(
            'description' => 'Informacion que se presenta al lateral de cada producto.',
            'name'        => 'InfoProducto',
            );

        parent::__construct('InfoProducto', '', $params );

        add_action('admin_enqueue_scripts', array($this, 'upload_scripts'));
        add_action('admin_enqueue_styles', array($this, 'upload_styles'));
    }

    /**
     * Upload the Javascripts for the media uploader
     */
    public function upload_scripts()
    {
        wp_enqueue_script('media-upload');
        wp_enqueue_script('thickbox');
        wp_enqueue_script('upload_media_widget', plugin_dir_url(__FILE__) . 'upload-media.js', array('jquery'));
    }

    /**
     * Add the styles for the upload media box
     */
    public function upload_styles()
    {
        wp_enqueue_style('thickbox');
    }

    public function form( $instance ){
        $title = __('Widget Image');
        if(isset($instance['title']))
        {
            $title = $instance['title'];
        }

        $image = '';
        if(isset($instance['image']))
        {
            $image = $instance['image'];
        }
/*
        $image2 = '';
        if(isset($instance['image2']))
        {
            $image2 = $instance['image2'];
        }

        $pdf = '';
        if(isset($instance['pdf']))
        {
            $pdf = $instance['pdf'];
        }*/
        ?>
        <p>
            <label for="<?php echo $this->get_field_name( 'title' ); ?>"><?php _e( 'Titulo:' ); ?></label>
            <input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $title ); ?>" />
        </p>

        <p>
            <label for="<?php echo $this->get_field_name( 'image' ); ?>"><?php _e( 'Imagen 1:' ); ?></label>
            <input name="<?php echo $this->get_field_name( 'image' ); ?>" id="<?php echo $this->get_field_id( 'image' ); ?>" class="widefat" type="text" size="36"  value="<?php echo esc_url( $image ); ?>" />
            <input class="upload_image_button button button-primary" type="button" value="Cargar Imagen" />
        </p>

      <!--  <p>
            <label for="<?php echo $this->get_field_name( 'pdf' ); ?>"><?php _e( 'PDF Informacion Nutricional:' ); ?></label>
            <input name="<?php echo $this->get_field_name( 'pdf' ); ?>" id="<?php echo $this->get_field_id( 'pdf' ); ?>" class="widefat" type="text" size="36"  value="<?php echo esc_url( $pdf ); ?>" />
            <input class="upload_pdf_button button button-primary" type="button" value="Cargar PDF" />
        </p>

         <p>
            <label for="<?php echo $this->get_field_name( 'image2' ); ?>"><?php _e( 'Imagen 2:' ); ?></label>
            <input name="<?php echo $this->get_field_name( 'image2' ); ?>" id="<?php echo $this->get_field_id( 'image2' ); ?>" class="widefat" type="text" size="36"  value="<?php echo esc_url( $image2 ); ?>" />
            <input class="upload_image_button button button-primary" type="button" value="Cargar Imagen" />
        </p> -->
    <?php
    }

    public function widget( $args, $instance ){

    }

    /**
     * Deals with the settings when they are saved by the admin. Here is
     * where any validation should be dealt with.
     *
     * @param array  An array of new settings as submitted by the admin
     * @param array  An array of the previous settings
     * @return array The validated and (if necessary) amended settings
     **/
    public function update( $new_instance, $old_instance ) {

        // update logic goes here
        $updated_instance = $new_instance;
        return $updated_instance;
    }
}

add_action('widgets_init', function(){
    register_widget( 'InfoProducto' );
}); 

 ?>

使用媒体库加载厚盒的javascript

jQuery(document).ready(function($) {
    $(document).on("click", ".upload_image_button", function() {

        jQuery.data(document.body, 'prevElement', $(this).prev());

        window.send_to_editor = function(html) {
            var imgurl = jQuery('img',html).attr('src');
            var inputText = jQuery.data(document.body, 'prevElement');

            if(inputText != undefined && inputText != '')
            {
                inputText.val(imgurl);
            }

            tb_remove();
        };

        tb_show('', 'media-upload.php?type=image&TB_iframe=true');
        return false;
    });
});

问题是，当我点击Cargar Imagen按钮时，没有任何内容加载，并且没有控制台错误消息。 我知道我做错了什么？

提前感谢！