WordPress:Function Reference/add meta box

Description

The add_meta_box() function was introduced in WordPress 2.5. It allows plugin developers to add sections to the Write Post, Write Page, and Write Link editing pages.

Usage

%%% <?php add_meta_box('id', 'title', 'callback', 'page', 'context'); ?> %%%

Example

Here is an example that adds a custom section to the post and page editing screens. It will will work with WordPress 2.5 and also with earlier versions of WordPress (when the add_meta_box function did not exist).

<?php
/* Use the admin_menu action to define the custom boxes */
add_action('admin_menu', 'myplugin_add_custom_box');

/* Use the save_post action to do something with the data entered */
add_action('save_post', 'myplugin_save_postdata');

/* Adds a custom section to the "advanced" Post and Page edit screens */
function myplugin_add_custom_box() {

  if( function_exists( 'add_meta_box' )) {
    add_meta_box( 'myplugin_sectionid', __( 'My Post Section Title', 'myplugin_textdomain' ), 
                'myplugin_inner_custom_box', 'post', 'advanced' );
    add_meta_box( 'myplugin_sectionid', __( 'My Post Section Title', 'myplugin_textdomain' ), 
                'myplugin_inner_custom_box', 'page', 'advanced' );
   } else {
    add_action('dbx_post_advanced', 'myplugin_old_custom_box' );
    add_action('dbx_page_advanced', 'myplugin_old_custom_box' );
  }
}
   
/* Prints the inner fields for the custom post/page section */
function myplugin_inner_custom_box() {

  // Use nonce for verification

  echo '<input type="hidden" name="myplugin_noncename" id="myplugin_noncename" value="' . 
    wp_create_nonce( plugin_basename(__FILE__) ) . '" />';

  // The actual fields for data entry

  echo '<label for="myplugin_new_field">' . __("Description for this field", 'myplugin_textdomain' ) . '</label> ';
  echo '<input type="text" name="myplugin_new_field" value="whatever" size="25" />';
}

/* Prints the edit form for pre-WordPress 2.5 post/page */
function myplugin_old_custom_box() {

  echo '<div class="dbx-b-ox-wrapper">' . "\n";
  echo '<fieldset id="myplugin_fieldsetid" class="dbx-box">' . "\n";
  echo '<div class="dbx-h-andle-wrapper"><h3 class="dbx-handle">' . 
        __( 'My Post Section Title', 'myplugin_textdomain' ) . "</h3></div>";   
   
  echo '<div class="dbx-c-ontent-wrapper"><div class="dbx-content">';

  // output editing form

  myplugin_inner_custom_box();

  // end wrapper

  echo "</div></div></fieldset></div>\n";
}

/* When the post is saved, saves our custom data */
function myplugin_save_postdata( $post_id ) {

  // verify this came from the our screen and with proper authorization,
  // because save_post can be triggered at other times

  if ( !wp_verify_nonce( $_POST[myplugin_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;
  }

  // OK, we're authenticated: we need to find and save the data

  $mydata = $_POST['myplugin_new_field'];

  // TODO: Do something with $mydata

   return $mydata;
}

Parameters

$id

(string) HTML 'id' attribute of the edit screen section

title

(string) Title of the edit screen section, visible to user

callback

(string) Function that prints out the HTML for the edit screen section.

page

(string) The type of Write screen on which to show the edit screen section ('post', 'page', or 'link')

context

(string) The part of the page where the edit screen section should be shown ('normal' or 'advanced')

Further Reading

• WordPress:Migrating Plugins and Themes
• WordPress:Function Reference