PDF.js Processing
RadPdfViewer uses the PDF.js library in order to process the passed pdf files. The PDF.js is an open-source project that is developed by Mozilla. This is why adding the PDF.js library scripts to the page is mandatory.
Make sure that the required by the RadPdfViewer PDF.js scripts are registered to the page.
In the following example you will see how to configure the PDFViewer to use PDF.js processing.
Example 1: Configure RadPdfViewer to use PDF.js
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.2.2/pdf.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.2.2/pdf.worker.js"></script>
<script>
window.pdfjsLib.GlobalWorkerOptions.workerSrc = 'https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.2.2/pdf.worker.js';
</script>
<telerik:RadPdfViewer runat="server" ID="RadPdfViewer1" RenderMode="Lightweight" Height="550px" Width="900px">
<PdfjsProcessingSettings File="Document.pdf">
</PdfjsProcessingSettings>
</telerik:RadPdfViewer>