developing a widget to show image

hi. i made a widget to show images in the front page of any site, very simple (Title,text and image) it works right now if i copy the link image and paste in the url input in the widget editor. But im following this tut to use a button to go to the media library and select the image but its not working. I mean, there is no iframe window to select the image from the library.

this is the tutorial https://codestag.com/how-to-use-wordpress-3-5-media-uploader-in-theme-options/

Cant see why its now working. Its reading the JS because i put an alarm and it works

these is the widget code

?php
/*
Plugin Name: Imagenx Media Upload
Plugin URI: http://behance.com/agarban
Description: Muestra imagenes.
Version: 1.0
Author: Alexei Garban
Author URI: http://behance.com/agarban
License: MIT
*/

/**
 * Creamos el widget
 *
 */
class WP_Widget_imagenx extends WP_Widget {

/**
     * Constructor
     **/
    public function __construct()
    {
        $widget_ops = array(
            'classname' => 'imagenx',
            'description' => 'Widget that uses the built in Media library.'
        );

        parent::__construct( 'imagenx', 'Imagenx Upload', $widget_ops );

        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_media();
        wp_enqueue_script('media-upload');
        wp_enqueue_script('thickbox');
        wp_enqueue_script('upload_media_widget', plugin_dir_url(__FILE__) . 'imagenx.js', array('jquery'));
    }

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

function widget($args, $instance)
{
	// Extraemos los argumentos del area de widgets
        extract($args);

        $titulo = apply_filters('widget_title', $instance['titulo']);
        $texto = $instance['texto'];
        $imagen = $instance['imagen'];
        $imagenx = $instance['imagenx'];

       ?>

<img src="<?php echo $imagenx; ?>">
<!--  -->

        <?php

}

	function update($new_instance, $old_instance)
{
	return array(
		'titulo'          => strip_tags($new_instance['titulo']),
		'texto'  => strip_tags($new_instance['texto']),
		'imagen'   => strip_tags ($new_instance['imagen']),
		'imagenx'   => strip_tags ($new_instance['imagenx']),
	);
}

function form($instance)
{
	// Obligamos a $instance a ser un array con todas las opciones disponibles
	$instance = wp_parse_args( (array) $instance, array(
					'titulo'  => 'Titulo',
					'texto'   => 'texto',
					'imagen'  => 'url',
					'imagenx'  => 'aqui',
	));

	// Filtramos los valores para que se muestren correctamente en los formularios
	$instance['titulo'] = esc_attr($instance['titulo']);
	$instance['texto'] = esc_attr($instance['texto']);
	$instance['imagen'] = esc_attr($instance['imagen']);
	$instance['imagenx'] = esc_attr($instance['imagenx']);

	// Mostramos el formulario
	?>

	<p>
		<label for="<?php echo $this->get_field_id('titulo'); ?>">Título:</label></p>
		<input value="<?php echo $instance['titulo']; ?>" class="widefat" type="text" id="<?php echo $this->get_field_id('titulo'); ?>" name="<?php echo $this->get_field_name('titulo'); ?>">
	</p>

	<p>
		<label for="<?php echo $this->get_field_id('texto'); ?>">Escribe Texto:</label></p>
		<input value="<?php echo $instance['texto']; ?>" class="widefat" type="text" id="<?php echo $this->get_field_id('texto'); ?>" name="<?php echo $this->get_field_name('texto'); ?>">
	</p>

	<p>
		<label for="<?php echo $this->get_field_id('imagen'); ?>">Url de la imagen:</label></p>
		<input value="<?php echo $instance['imagen']; ?>" class="widefat" type="text" id="<?php echo $this->get_field_id('imagen'); ?>" name="<?php echo $this->get_field_name('imagen'); ?>">
	</p>

	 <p>
            <label for="<?php echo $this->get_field_name( 'imagenx' ); ?>"><?php _e( 'Imagenx:' ); ?></label>
            <input value="<?php echo $instance['imagenx']; ?>" class="widefat" type="text" id="<?php echo $this->get_field_id('imagenx'); ?>" name="<?php echo $this->get_field_name('imagenx'); ?>">

            <input class="upload_image_button button button-primary" type="button" value="Upload Image" />
        </p>

	<?php
}

}

/**
 * Registramos el widget (Si no lo hacemos, WordPress no podrá detectarlo)
 *
 */
function widget_register_imagenx()
{
	register_widget('WP_Widget_imagenx');
}
add_action('widgets_init', 'widget_register_imagenx');

//FIN
?>

and the JS

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

       // alert("Mouse down over p1!");

        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;
    });
});