Add meta fields to quick edit

add_quickedit_column.php

add_action( 'quick_edit_custom_box', 'display_custom_quickedit_featured', 10, 2 );

function display_custom_quickedit_featured( $column_name, $post_type ) {
    static $printNonce = TRUE;
    if ( $printNonce ) {
        $printNonce = FALSE;
        wp_nonce_field( plugin_basename( __FILE__ ), 'post_edit_nonce' );
    }

    ?>
    <fieldset class="inline-edit-col-right inline-edit-featured">
      <div class="inline-edit-col column-<?php echo $column_name; ?>">
        <label class="inline-edit-group">
        <?php 
         switch ( $column_name ) {
         case 'featured':
             ?><span class="title">Featured</span><input name="featured_position" /><?php
             break;
         }
        ?>
        </label>
      </div>
    </fieldset>
    <?php
}

add_action( 'save_post', 'save_post_featured' );
function save_post_featured( $post_id ) {
    $slug = 'post';
    if ( $slug !== $_POST['post_type'] ) {
        return;
    }
    if ( !current_user_can( 'edit_post', $post_id ) ) {
        return;
    }
    $_POST += array("{$slug}_edit_nonce" => '');
    if ( !wp_verify_nonce( $_POST["{$slug}_edit_nonce"], plugin_basename( __FILE__ ) ) )  {
        return;
    }

    if ( isset( $_REQUEST['featured_position'] ) ) {
        update_post_meta( $post_id, 'featured_position', $_REQUEST['featured_position'] );
    } else {
        delete_post_meta($post_id, 'featured_position');
    }
    # checkboxes are submitted if checked, absent if not
}
add_action('admin_footer', 'grafa_quick_edit_javascript');


/* load script in the footer */
if ( ! function_exists('wp_my_admin_enqueue_scripts') ):
function wp_my_admin_enqueue_scripts( $hook ) {

    if ( 'edit.php' === $hook ) {

        wp_enqueue_script( 'my_custom_script', get_stylesheet_directory_uri().'/assets/js/admin_edit.js', false, null, true );

    }

}
endif;
add_action( 'get_footer', 'wp_my_admin_enqueue_scripts' );

admin_edit.js

(function($) {

	// we create a copy of the WP inline edit post function
	var $wp_inline_edit = inlineEditPost.edit;

	// and then we overwrite the function with our own code
	inlineEditPost.edit = function( id ) {

		// "call" the original WP edit function
		// we don't want to leave WordPress hanging
		$wp_inline_edit.apply( this, arguments );

		// now we take care of our business

		// get the post ID
		var $post_id = 0;
		if ( typeof( id ) == 'object' ) {
			$post_id = parseInt( this.getId( id ) );
		}

		if ( $post_id > 0 ) {
			// define the edit row
			var $edit_row = $( '#edit-' + $post_id );
			var $post_row = $( '#post-' + $post_id );

			// get the data
			var $featured = $( '.column-featured', $post_row ).text();

			// populate the data
			$( ':input[name="featured_position"]', $edit_row ).val( $featured );

		}
	};

})(jQuery);