Looking for a way to make the TinyMCE editor always relative to it's content so that the height of the editor changes accordingly to how much text/images it contains.

There seem to be plugins for TinyMCE for this already, but I'm not sure on how to apply it for the Wordpress version: http://www.tinymce.com/wiki.php/Plugin:autoresize

function init_tinymce_autoresize($initArray){
   $initArray['plugins'] = "autoresize";
   return $initArray;
add_filter('tiny_mce_before_init', 'init_tinymce_autoresize');

Does not work.


  • Not that it helps answer your question, but you could be clobbering other plugins with that code. In my case, $initArray['plugins'] is already populated when the tiny_mce_before_init filter is called. You may be safer appending ",autoresize" (it seems to be a comma-delimited string) if it's not empty. – Hobo Nov 17 '12 at 15:04
  • I had a problem with the editor resizing on every keypress (including cursors). I didn't solve it, but kept a little sanity by adding $initArray['autoresize_max_height'] = '500'; to the init_tinymce_autoresize function above (in case it helps someone else). – Hobo Nov 17 '12 at 15:49
  • @Hobo I know I would overwrite other plugins by doing as I initially wrote in the question, that was just for debugging purposes. As autoresize isn't part of TinyMCE for Wordpress it wouldn't work however I tried it. The plugin I wrote below does however work. – INT Nov 17 '12 at 16:07
  • fair enough. I'm just grateful for your solution (and timing - I can't believe you only asked this two days ago). Thanks! – Hobo Nov 17 '12 at 16:09

Here's a solution. There's a slight problem as it does not recognize when images are added to the editor.

1: Create a folder with the name tinymce-autoresize in the plugins folder.
2. Create a file in tinymce-autoresize named tinymce_autoresize.php with this content:

function intialize_autoresize_plugin() {
    // Check user permission
    if ( ! current_user_can('edit_posts') && ! current_user_can('edit_pages') )

    // Add only in Rich Editor mode
    if ( get_user_option('rich_editing') == 'true') {
        add_filter("mce_external_plugins", "autoresize_plugin_load");

function autoresize_plugin_load($plugin_array) {
    $plug = WP_PLUGIN_URL . '/tinymce-autoresize/editor_plugin.js'; 
    $plugin_array['autoresize'] = $plug;
    return $plugin_array;

add_action('init', 'intialize_autoresize_plugin');

3. Create a file in tinymce-autoresize named editor_plugin.js with this content:

 * editor_plugin_src.js
 * Copyright 2009, Moxiecode Systems AB
 * Released under LGPL License.
 * License: http://tinymce.moxiecode.com/license
 * Contributing: http://tinymce.moxiecode.com/contributing

(function() {
     * Auto Resize
     * This plugin automatically resizes the content area to fit its content height.
     * It will retain a minimum height, which is the height of the content area when
     * it's initialized.
    tinymce.create('tinymce.plugins.AutoResizePlugin', {
         * Initializes the plugin, this will be executed after the plugin has been created.
         * This call is done before the editor instance has finished it's 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) {
            var t = this, oldSize = 0;

            if (ed.getParam('fullscreen_is_enabled'))

             * This method gets executed each time the editor needs to resize.
            function resize() {
                var deltaSize, d = ed.getDoc(), body = d.body, de = d.documentElement, DOM = tinymce.DOM, resizeHeight = t.autoresize_min_height, myHeight;

                // Get height differently depending on the browser used
                myHeight = tinymce.isIE ? body.scrollHeight : (tinymce.isWebKit && body.clientHeight == 0 ? 0 : body.offsetHeight);

                // Don't make it smaller than the minimum height
                if (myHeight > t.autoresize_min_height)
                    resizeHeight = myHeight;

                // If a maximum height has been defined don't exceed this height
                if (t.autoresize_max_height && myHeight > t.autoresize_max_height) {
                    resizeHeight = t.autoresize_max_height;
                    body.style.overflowY = "auto";
                    de.style.overflowY = "auto"; // Old IE
                } else {
                    body.style.overflowY = "hidden";
                    de.style.overflowY = "hidden"; // Old IE
                    body.scrollTop = 0;

                // Resize content element
                if (resizeHeight !== oldSize) {
                    deltaSize = resizeHeight - oldSize;
                    DOM.setStyle(DOM.get(ed.id + '_ifr'), 'height', resizeHeight + 'px');
                    oldSize = resizeHeight;

                    // WebKit doesn't decrease the size of the body element until the iframe gets resized
                    // So we need to continue to resize the iframe down until the size gets fixed
                    if (tinymce.isWebKit && deltaSize < 0)

            t.editor = ed;

            // Define minimum height
            t.autoresize_min_height = parseInt(ed.getParam('autoresize_min_height', ed.getElement().offsetHeight));

            // Define maximum height
            t.autoresize_max_height = parseInt(ed.getParam('autoresize_max_height', 0));

            // Add padding at the bottom for better UX
                ed.dom.setStyle(ed.getBody(), 'paddingBottom', ed.getParam('autoresize_bottom_margin', 25) + 'px');

            // Add appropriate listeners for resizing content area

            if (ed.getParam('autoresize_on_init', true)) {
            //  ed.onLoad.add(resize);

            // Register the command so that it can be invoked by using tinyMCE.activeEditor.execCommand('mceExample');
            ed.addCommand('mceAutoResize', resize);

         * Returns information about the plugin as a name/value array.
         * The current keys are longname, author, authorurl, infourl and version.
         * @return {Object} Name/value array containing information about the plugin.
        getInfo : function() {
            return {
                longname : 'Auto Resize',
                author : 'Moxiecode Systems AB',
                authorurl : 'http://tinymce.moxiecode.com',
                infourl : 'http://wiki.moxiecode.com/index.php/TinyMCE:Plugins/autoresize',
                version : tinymce.majorVersion + "." + tinymce.minorVersion

    // Register plugin
    tinymce.PluginManager.add('autoresize', tinymce.plugins.AutoResizePlugin);

Activate it and you're done!

| improve this answer | |
  • I didi exactly that, inside wp-content/plugins/, then activated the plugins with no error but the TinyMCE textareas don't expand when writing. – Bachir Messaouri Oct 26 '17 at 23:25

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