test.cshtml

@using TXTextControl.Web.MVC

@Html.TXTextControl().TextControl().Render()

<button onclick="loadDocument()">Load Document</button>

<script>

    function loadDocument() {
        var xmlhttp = new XMLHttpRequest();
        xmlhttp.open("GET", "Home/LoadDocument", true);
        xmlhttp.onreadystatechange = function () {
            if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
                TXTextControl.loadDocument(
                    TXTextControl.StreamType.InternalUnicodeFormat,
                    xmlhttp.responseText);
            }
        }
        
        xmlhttp.send();
    }   

</script>