Demo

Source Code

    <textarea name="editor1" id="editor1" rows="10"></textarea>
    <script>
    CKEDITOR.replace('editor1', {
        toolbarGroups: [
            {name: 'tools'},
            {name: 'links'},
            {name: 'basicstyles', groups: ['basicstyles', 'cleanup']},
            {name: 'paragraph',   groups: [ 'list', 'indent', 'blocks', 'align', 'bidi' ]},
            {name: 'styles'},
            {name: 'others'}
        ],
        extraPlugins: 'markdown'
    });
    </script>