WordPress: TinyMCE button that wraps selection in given tag

editor_plugin.js

// http://tinymce.moxiecode.com/wiki.php/API3:class.tinymce.Plugin

(function() {

	tinymce.create('tinymce.plugins.WRAP', {
		/**
		 * Initializes the plugin, this will be executed after the plugin has been created.
		 * This call is done before the editor instance has finished its initialization so use the onInit event
		 * of the editor instance to intercept that event.
		 *
		 * @param {tinymce.Editor} ed Editor instance that the plugin is initialized in.
		 * @param {string} url Absolute URL to where the plugin is located.
		 */
		init : function(ed, url) {

			//this command will be executed when the button in the toolbar is clicked
			ed.addCommand('mceWRAP', function() {

				selection = tinyMCE.activeEditor.selection.getContent();

				//prompt for a tag to use
				//tag = prompt('Tag:');
				//tinyMCE.activeEditor.selection.setContent('<' + tag + '>' + selection + '</' + tag + '>');

				tinyMCE.activeEditor.selection.setContent('<div class="classy-div">' + selection + '</div>');

			});

			ed.addButton('WRAP', {
				title : 'WRAP.desc',
				cmd : 'mceWRAP',
				//image : url + '/your-icon.gif'
				image : 'http://mdawg123.wikispaces.com/i/icon_16_gear.gif'
			});

		},

	});

	// Register plugin
	tinymce.PluginManager.add('WRAP', tinymce.plugins.WRAP);
})();

mce-wrapper.php

<?php
/*
Plugin Name: MCE Wrapper
Plugin URI: http://trepmal.com/
Description: TinyMCE button that wraps selection in given tag
Author: Kailey Lampert
Version: 1.0
Author URI: http://kaileylampert.com/

Copyright (C) 2011  Kailey Lampert

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

add_action( 'init', 'mce_wrapper_init', 9);
function mce_wrapper_init() {
	if (is_admin())
		new mcewrapper();
}

class mcewrapper {

	var $pluginname = 'WRAP';
	var $internalVersion = 600;

	/**
	 * mcewrapper::mcewrapper()
	 * the constructor
	 *
	 * @return void
	 */
	function mcewrapper()  {

		// Modify the version when tinyMCE plugins are changed.
		add_filter('tiny_mce_version', array (&$this, 'change_tinymce_version') );

		// init process for button control
		add_action('init', array (&$this, 'addbuttons') );

	}

	/**
	 * mcewrapper::addbuttons()
	 *
	 * @return void
	 */
	function addbuttons() {

		// Don't bother doing this stuff if the current user lacks permissions
		if ( !current_user_can('edit_posts') && !current_user_can('edit_pages') )
			return;

		// Add only in Rich Editor mode
		if ( get_user_option('rich_editing') == 'true') {

			// add the button for wp2.5 in a new way
			add_filter("mce_external_plugins", array (&$this, 'add_tinymce_plugin' ));
			add_filter('mce_buttons', array (&$this, 'register_button' ), 0);
		}
	}

	/**
	 * mcewrapper::register_button()
	 * used to insert button in wordpress 2.5x editor
	 *
	 * @return $buttons
	 */
	function register_button($buttons) {

		array_push($buttons, 'separator', $this->pluginname );

		return $buttons;
	}

	/**
	 * mcewrapper::add_tinymce_plugin()
	 * Load the TinyMCE plugin : editor_plugin.js
	 *
	 * @return $plugin_array
	 */
	function add_tinymce_plugin($plugin_array) {

		$plugin_array[$this->pluginname] =  plugins_url( 'editor_plugin.js', __FILE__ );

		return $plugin_array;
	}

	/**
	 * mcewrapper::change_tinymce_version()
	 * A different version will rebuild the cache
	 *
	 * @return $version
	 */
	function change_tinymce_version($version) {
		$version = $version + $this->internalVersion;
		return $version;
	}


}