test.js

function saveDocument() {
    // save document
    TXTextControl.saveDocument(TXTextControl.StreamType.AdobePDF, function (e) {
        // create temporary link element
        var element = document.createElement('a');
        element.setAttribute('href', 'data:application/octet-stream;base64,' + e.data);
        element.setAttribute('download', "results.pdf");

        element.style.display = 'none';
        document.body.appendChild(element);

        // simulate click
        element.click();

        // remove the link
        document.body.removeChild(element);
    });
}

function loadDocument() {

    const htmlDocument = "<p>Hello <strong>World!</strong></p>";

    TXTextControl.loadDocument(TXTextControl.StreamType.HTMLFormat,
        window.btoa(htmlDocument));
}