<div id="form_here">
</div>
<textarea id="area"></textarea>

<script>
    var form = document.createElement('form');
    form.setAttribute('acton', 'http://bla.test.ru');
    form.setAttribute('method', 'post');
    form.setAttribute('enctype', 'multipart/form-data');
    var inp = document.createElement('input');
    inp.setAttribute('type', 'text');
    inp.setAttribute('name', 'email');
    form.appendChild( inp );

    var block = document.getElementById('form_here');
    block.appendChild( form );

    document.getElementById('area').value = block.innerHTML;
    
</script>