Render.cshtml

<link href="https://fonts.googleapis.com/css?family=Open+Sans:400,300italic,400italic,600italic,700italic,300,600,700,800" rel="stylesheet">
<link rel="stylesheet" type="text/css" href="/sitecore/shell/themes/standard/default/Default.css" />
<link rel="stylesheet" type="text/css" href="/sitecore/shell/themes/standard/default/Content Manager.css" />
<style>
    #ll-fields {
        padding: 10px 10px 10px 10px;
    }
</style>
<div id="ll-fields" class="scEditorSections">
    <div class="scEditorFieldMarker">
        <div class="scEditorFieldLabel">Text:</div>
        <div>
            <input type="text" id="ll-text" class="scContentControl scCombobox" />
        </div>
    </div>
</div>

<script type="text/javascript" src="/scripts/field/field-base.js"></script>
<script type="text/javascript" src="/scripts/field/text-field.js"></script>
<script>
    textField.getValue();

    document.getElementById('ll-text').onchange = function () {
        textField.setValue();
    };

    textField.updateIframeDisplaySettings();
</script>