Uso de editor ACE

ace.html

<form>
    <textarea name="contenido" style="display: none;"></textarea>
</form>
<div id="editor-codigo" style="height: 500px; width: 100%"></div>
<script>
    var editor = ace.edit("editor-codigo");
    editor.setTheme("ace/theme/monokai");
    editor.session.setMode("ace/mode/html");
    editor.session.setMode("ace/mode/css");
    
    $("form").on("submit", function (e) {
        $('textarea[name="contenido"]').val(editor.getValue());
    });
</script>