How to convert an ASP or JSP page to PDF?

The pdfHTML add-on parses HTML and CSS. That's it.

ASP.Net, JSP, MVC, Razor, Struts, Spring, etc, are all HTML frameworks iText and pdfHTML are 100% unaware of. The same goes for DataGridViews, Repeaters, Templates, Views, etc. which are all framework-specific abstractions. It is not up to pdfHTML—nor iText for that matter—to interpret ASP, JSP, or any other syntax.

It is your responsibility to get the HTML from your choice of framework. If you have an ASP file, run it through your ASP framework to create the HTML. The pdfHTML add-on will gladly accept that HTML for conversion to PDF.