Get Started with the Document Viewer Demo - HTML5 JavaScript

This tutorial shows how to configure and run the LEADTOOLS Document Viewer Demo with the Document Service.

Summary This tutorial covers how to properly run the LEADTOOLS Document Viewer Demo.
Completion Time 5 - 10 minutes
Platform HTML5/JS
IDE Visual Studio 2017, 2019
Development License Download LEADTOOLS

Required Knowledge

Be sure to download and install the LEADTOOLS SDK, and make sure that your license and key files are located in your <INSTALL_DIR>\LEADTOOLS22\Support\Common\License directory.

Open the Document Viewer Demo

The installed LEADTOOLS SDK includes the HTML5/JavaScript Document Viewer Demo which showcases many of the features that the SDK offers.

To start off, navigate to the demo in File Explorer. Once the LEADTOOLS SDK is installed, the demo can be found at the following directory:


The demo includes a DocumentViewerDemo.sln solution file. This Visual Studio solution contains 2 C# ASP.NET Projects, one written in TypeScript (DocumentViewerTypeScript), and one written in JavaScript (DocumentViewer).

Open the Solution in Visual Studio and explore the resources and options already available. Decide on which type of project to compile, and whether to use the TypeScript demo.

The TypeScript demo, when modified and built, will compile into the JavaScript project. The TypeScript project version is a good choice for simplifying code reading, debugging, and overall project development. In general, the TypeScript platform provides highly productive development tools for JavaScript IDEs and practices, like static checking while making the code easier to read. However, if the TypeScript project is not desired, it is not needed and can simply be unloaded from the solution or deleted.

Set up and Configure the Demo with the Document Service

The Document Viewer Demo relies on a server-side backend for some of its functionality:

The Document Service is written in 3 different languages. Each Service uses a different Port, by default, when deploying.

Language Path to Service Project Default Url Compatible OS
.NET Framework <INSTALL_DIR>\LEADTOOLS22\Examples\Document\JS\DocumentServiceDotNet\fx http://localhost:40000/ Windows
.NET Core <INSTALL_DIR>\LEADTOOLS22\Examples\Document\JS\DocumentServiceDotNet\core http://localhost:30000/ Windows, Linux, Mac
Java <INSTALL_DIR>\LEADTOOLS22\Examples\Document\JS\DocumentServiceJava http://localhost:8080/ Windows, Linux, Mac

By default, the Document Viewer Demo is configured to work with the .NET Framework service. To change the URL to work with another service URL, simply open <INSTALL_DIR>\LEADTOOLS22\Examples\Viewers\JS\DocumentViewerDemo\site\serviceConfig.json and modify the serviceHost value to the correct URL:

   "serviceHost": "http://localhost:40000", 
   "servicePath": "", 
   "serviceApiPath": "api", 

Run the .NET Framework Document Service

The .NET Framework Document Service has 2 different projects that can be opened. The DocumentService.csproj uses local references from <INSTALL_DIR>\LEADTOOLS22\Bin\Dotnet4\<CPU_ARCH>, and the DocumentService_Nuget.csproj uses NuGet Packages. Choose the one to be used, and open it in Visual Studio.

Run the project through Visual Studio and explore the resources and options already available. Decide on the type of project to compile, and whether to use the NuGet Packages.

Run the .NET Core Document Service

The .NET Core Document Service DocumentService.csproj uses NuGet Packages. This project can be built and run on any operating system that has .NET Core installed on it. It can be run through Visual Studio on Windows via IIS Express.

When running on Linux or outside of Visual Studio, run dotnet publish from the development environment to package the application into a directory (for example, bin\Debug\netcoreapp2.1\publish). Copy the new publish directory to the machine in the desired location, then test the application using dotnet DocumentService.dll and browse to the URL.

Run the Java Document Service

To set up the Java Environment for use with the LEADTOOLS Document Service, refer to the PDF located here: <INSTALL_DIR>\LEADTOOLS22\Examples\Document\JS\Services\Help\JavaDocumentViewerSetup.pdf

Run the Viewer Project with a Service

Now that the Document Service is running and the Document Viewer Demo is properly set up to use the URL in the serviceConfig.Json file as described in the steps above, run the Document Viewer Demo via Visual Studio.

When it launches, it will connect to the service and load a default PDF. If there are any issues during the setup, this is typically where they will appear.


If the Document Service is not running when launching the Document Viewer Demo, a dialog will open in the browser with the message Cannot reach the LEADTOOLS Document Service. Retry the steps above to verify the Document Viewer Demo is using the correct URL and that the service is actively running. If both are set up correctly, check the Console in the Browse Dev Tools (F12) for any errors listed.

Load Documents

Once everything is set up and the default PDF is loaded into the viewer, other documents and images can now be loaded via the File menu. There are 4 different methods of loading a document:

Dialog menu of the 4 different methods:

There are 4 different methods of loading a document

The following table describes the 4 methods:

Menu Item Description
Open local file Open a local file from the client system
Open from URL Open a file from a URL
Open from cache Open a file that has been saved to the Document Viewer cache on the server
Open from cloud storage Open from a connected cloud provider such as SharePoint, Google Drive, or One Drive

Export Documents

When a Document is ready to be saved, it can be exported to a different format than the original. To do so, open the File menu, choose Export and choose the desired options.

Open the File menu and choose Export and the desired options

Change the Properties

The Document Viewer demo has many settings and options that can be adjusted as needed. There are both client-side settings and server-side settings. In the case where there is a setting on both the server-side and client-side, the server-side settings take precedence.

Change Client-Side Properties

Select the Preferences menu item and then click on the Document Viewer Options. Modify any settings as necessary and then click Apply to enact the changes.

Modify any settings as necessary and then click Apply to enact the changes

Change Server-side Properties

In the Server project, modify the settings with any of the following files:

Language Path to Settings File
.NET Framework \LEADTOOLS22\Examples\Document\JS\DocumentServiceDotNet\src\appsettings.json
.NET Core \LEADTOOLS22\Examples\Document\JS\DocumentServiceDotNet\src\appsettings.json
Java \LEADTOOLS22\Examples\Document\JS\DocumentServiceJava\document-service\src\main\resources\


When modifying the properties of the .NET Framework and the .NET Core projects, be sure that the file being modified is the one in the \DocumentServiceDotNet\src\ folder and not in the \DocumentServiceDotNet\fx or \DocumentServiceDotNet\core folders, as those are just copies of the src\appsettings.json. Any modifications to them gets overwritten by the src\appsettings.json file upon build.


This tutorial showed how to connect and configure the LEADTOOLS Document Viewer Demo to the Document Service and how to load and export a document, as well as modify the settings on both the client-side and server-side.

See Also

Help Version 22.0.2024.3.20
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.

Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.