layui_back/back/assets/module/ckeditor/plugins/preview/preview.html

<script>

    // Prevent from DOM clobbering.
    if (typeof window.opener._cke_htmlToLoad == 'string') {
        var doc = document;
        doc.open();
        doc.write(window.opener._cke_htmlToLoad);
        doc.close();

        delete window.opener._cke_htmlToLoad;
    }

</script>