Please note that HTML 5 Editor was just a demonstration of how you can implement API features in web application to view the PDF in HTML DOM. However, we have discontinued this application and are not maintaining it anymore.
You may please check Groupdocs Viewer application, offered by our sister company Groupdocs. There are other products as well, offered by our sister company which may be suitable, in order to meet your requirements.
With Aspose.PDF for .NET, you may implement its functionalities in code behind and use its features to accomplish your various requirements. In case you have any further query about Aspose.PDF for .NET, please feel free to ask.