tx.js

function LoadFromController(DocumentName) {
    var serviceURL = "/Home/LoadTemplate";

    $.ajax({
        type: "POST",
        url: serviceURL,
        contentType: 'application/json',
        data: JSON.stringify({
            DocumentName: DocumentName
        }),
        success: successFunc,
        error: errorFunc
    });

    function successFunc(data, status) {
        TXTextControl.loadDocument(
          TXTextControl.streamType.InternalUnicodeFormat, data);
        animateBackstage(1);
    }

    function errorFunc() {
        alert('File could not be loaded');
    }
}