demoexplorer1.cshtml

@Html.TXTextControl().DocumentViewer(settings =>
{
    settings.Dock = DocumentViewerSettings.DockStyle.Fill;
    settings.IsSelectionActivated = true;
    settings.ShowThumbnailPane = true;
}).Render()

<button onclick="LoadDocument('car_insurance.tx')" 
    class="btn mt-3 btn-success">Load Document</button>