Enable Disable (Readonly) TinyMCE Editor using JavaScript or Server Side

  <script type = "text/javascript" src="//tinymce.cachefly.net/4.0/tinymce.min.js"></script>
        <script type="text/javascript">
            tinymce.init({ selector: 'textarea' });
            var is_disabled = false;
            function enable_disable(btn) {
                is_disabled = !is_disabled;
                tinymce.activeEditor.getBody().setAttribute('contenteditable', !is_disabled);
                btn.value = is_disabled ? "Enable" : "Disable";
            }
        </script>
        <textarea>Your content here.</textarea>
        <input type="button" value="Disable" onclick = "enable_disable(this)" />