Limit the number of character in tinyMCE

This works in tinyMCE 4.3.12 and also captures pasting:

EDIT: Fixed bugs and extended code to display a character counter under the editor. Possibly not the best way as it relies a bit on the current HTML structure of tinyMCE having the editor div before the hidden textarea.

This version only counts the text length and ignores HTML tag length. To count full HTML length, replace all “innerText” with “innerHTML”.

tinymce.init({
    max_chars: 1000, // max. allowed chars
    setup: function (ed) {
        var allowedKeys = [8, 37, 38, 39, 40, 46]; // backspace, delete and cursor keys
        ed.on('keydown', function (e) {
            if (allowedKeys.indexOf(e.keyCode) != -1) return true;
            if (tinymce_getContentLength() + 1 > this.settings.max_chars) {
                e.preventDefault();
                e.stopPropagation();
                return false;
            }
            return true;
        });
        ed.on('keyup', function (e) {
            tinymce_updateCharCounter(this, tinymce_getContentLength());
        });
    },
    init_instance_callback: function () { // initialize counter div
        $('#' + this.id).prev().append('<div class="char_count" style="text-align:right"></div>');
        tinymce_updateCharCounter(this, tinymce_getContentLength());
    },
    paste_preprocess: function (plugin, args) {
        var editor = tinymce.get(tinymce.activeEditor.id);
        var len = editor.contentDocument.body.innerText.length;
        var text = $(args.content).text();
        if (len + text.length > editor.settings.max_chars) {
            alert('Pasting this exceeds the maximum allowed number of ' + editor.settings.max_chars + ' characters.');
            args.content="";
        } else {
            tinymce_updateCharCounter(editor, len + text.length);
        }
    }
});

function tinymce_updateCharCounter(el, len) {
    $('#' + el.id).prev().find('.char_count').text(len + "https://stackoverflow.com/" + el.settings.max_chars);
}

function tinymce_getContentLength() {
    return tinymce.get(tinymce.activeEditor.id).contentDocument.body.innerText.length;
}

Reference: How can I prevent tinyMCE’s paste event?