Add References and Set a License - HTML5 JavaScript

This tutorial shows how to set a LEADTOOLS runtime license using HTML5 and JavaScript. Before any functionality from the SDK can be leveraged, a valid runtime license will have to be set. For instructions on how to obtain a runtime license refer to Obtaining a License.

Summary This tutorial demonstrates how to set a LEADTOOLS runtime license using HTML5 and JavaScript.
Completion Time 15 minutes
Visual Studio Project Download tutorial project (1 KB)
Platform JavaScript Web Application
IDE Visual Studio 2017, 2019, Visual Studio Code - Client
Development License Download LEADTOOLS
Try it in another language

Required Knowledge

This tutorial makes use of http-server, a console command for running a static file server. Make sure that http-server is installed. If it is not installed, first install Node.js then install http-server. Below are their corresponding download links:

Create the Project

Create a project folder and include the following:

Add the License Files

Navigate into the newly-created LEADTOOLS folder. Copy and paste the LEADTOOLS.lic.txt and LEADTOOLS.lic.key.txt license files into the LEADTOOLS folder. Note that the licenses ending in .txt are for JavaScript. The license files that do not end in .txt are for server and desktop applications. The license files can be found in the following directory: <INSTALL_DIR>\LEADTOOLS21\Support\Common\License

Screenshot of LEADTOOLS directory with license files

Add LEADTOOLS Dependencies

Navigate to the newly-created lib folder. Copy and paste the Leadtools.js file from the <INSTALL_DIR>\LEADTOOLS21\Bin\Js\ folder. Leadtools.js is the kernel of the LEADTOOLS JavaScript support and is required by all other libraries.

Import the LEADTOOLS Logic and Dependencies

Open the index.html file in the project folder. Add the below necessary script tags inside the head to import the application logic and LEADTOOLS dependencies.

<!DOCTYPE html> 
<html lang="en"> 
    <meta charset="UTF-8" /> 
    <meta name="viewport" content="width=device-width, initial-scale=1.0" /> 
    <!--Import LEADTOOLS Dependencies--> 
    <script src="./lib/Leadtools.js"></script> 
    <!--Import Project Dependencies--> 
    <script src="./app.js"></script> 
    <title>Setting a LEADTOOLS License</title> 

Add the Set License Code

Open the app.js file in the project folder. This file is where the LEADTOOLS set license call will be added. Add the following code:

window.onload = function () { 
  var licenseUrl = "./Leadtools/LEADTOOLS.lic.txt"; 
  var developerKey = "ADD THE CONTENTS OF THE LEADTOOLS.lic.key.txt FILE"; 
  lt.RasterSupport.setLicenseUri(licenseUrl, developerKey, function ( 
  ) { 
    // Check the status of the license 
    if (setLicenseResult.result) { 
      console.log("LEADTOOLS client license set successfully"); 
    } else { 
      var msg = "LEADTOOLS License is missing, invalid or expired\nError:\n"; 

Important Note

Make sure to replace the value of the developerKey string with the contents of the license Key text file.

Run the Project

Open the Command Line, and navigate to the project folder. Use the following command to run a static file server.


The server should start and run on http:localhost:8080. A message should appear in the console indicating all of the ports that the server is available on.

Terminal message indicating server is running

Open the browser and navigate to http://localhost:8080/index.html. The following message is displayed to the developers console(F12) to inform that the license has been set successfully.

License Set Successfully displayed to the user


This tutorial showed how to set a client-side LEADTOOLS license in a HTML5/JS application.

See Also

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