Custom Write Panels

I’m having trouble getting my custom meta item to show up in the text area where it was saved after updating the page. (However, it does save as custom post meta and shows up in the custom fields area.)

Everything is based on this tutorial:https://wefunction.com/2008/10/tutorial-create-custom-write-panels-in-wordpress.

Any help is appreciated.

<?php

/*
Plugin Name: Custom Write Panel
Plugin URI: https://wefunction.com/2008/10/tutorial-create-custom-write-panels-in-wordpress
Description: Allows custom fields to be added to the WordPress Post Page
Version: 1.0
Author: Spencer
Author URI: https://wefunction.com
/* ----------------------------------------------*/  

$new_meta_boxes =
array(
"textarea" => array(
"name" => "scontent",
"std" => "",
"title" => "Sidebar Content",
"description" => "Add content to display in the sidebar.")
);

function new_meta_boxes() {
	global $post, $new_meta_boxes;  

	foreach($new_meta_boxes as $meta_box) {
		$meta_box_value = get_post_meta($post->ID, $meta_box['name'].'_value', true);  

		if($meta_box_value == "")
			$meta_box_value = $meta_box['std'];  

			echo'<input type="hidden" name="'.$meta_box['name'].'_noncename" id="'.$meta_box['name'].'_noncename" value="'.wp_create_nonce( plugin_basename(__FILE__) ).'" />';  

			echo'<p>'.$meta_box['title'].'</p>';  

			echo'<textarea name="'.$meta_box['name'].'_value" value="'.$meta_box_value.'" rows="1" cols="40" style="margin:0;height:4em;width:98%;"></textarea><br />';  

			echo'<p><label for="'.$meta_box['name'].'_value">'.$meta_box['description'].'</label></p>';
		}
	}  

function create_meta_box() {
	global $theme_name;
	if ( function_exists('add_meta_box') ) {
		add_meta_box( 'new-meta-boxes', 'Custom Settings', 'new_meta_boxes', 'page', 'normal', 'high' );
	}
}  

function save_postdata( $post_id ) {
	global $post, $new_meta_boxes;  

	foreach($new_meta_boxes as $meta_box) {
		// Verify
		if ( !wp_verify_nonce( $_POST[$meta_box['name'].'_noncename'], plugin_basename(__FILE__) )) {
			return $post_id;
		}  

		if ( 'page' == $_POST['post_type'] ) {
			if ( !current_user_can( 'edit_page', $post_id ))
				return $post_id;
			} else {
			if ( !current_user_can( 'edit_post', $post_id ))
				return $post_id;
			}  

	$data = $_POST[$meta_box['name'].'_value'];  

 	if(get_post_meta($post_id, $meta_box['name'].'_value') == "")
 		add_post_meta($post_id, $meta_box['name'].'_value', $data, true);
 	elseif($data != get_post_meta($post_id, $meta_box['name'].'_value', true))
 		update_post_meta($post_id, $meta_box['name'].'_value', $data);
 	elseif($data == "")
 		delete_post_meta($post_id, $meta_box['name'].'_value', get_post_meta($post_id, $meta_box['name'].'_value', true));
	}
}  

add_action('admin_menu', 'create_meta_box');
add_action('save_post', 'save_postdata');

?>