Overview of Creo.JS
In a previous release of Creo, the embedded browser, which was used to work with Web.Link applications was updated to run out of the Creo process. The inter-communication overheads caused some performance issues.
In Creo 4.0 M080 release and later, a new toolkit Creo.JS is available. Creo.JS engine helps to improve the performance of the existing Web.Link applications. To leverage the advantages of Creo.JS, you will have to update the existing Web.Link applications. The toolkit uses a Chrome V8 JavaScript engine, which runs inside the Creo process. This removes the inter-communication overheads. The engine supports the ECMAScript 2018 specification. Creo.JS framework runs Creo applications that are written in JavaScript.
Creo.JS Application
Creo.JS application is written in JavaScript. It is deployed on a single web page. It is a distributed application which consists of two parts:
•  JavaScript sections that control dynamic HTML user interface and user interaction. These scripts can contain combination of HTML browser APIs for DOM manipulation and Web.Link APIs. This part of the application runs in the browser.
•  JavaScript sections that interact with the Creo toolkit APIs. These scripts are loaded in the Creo process and are executed by the Creo.JS engine, which is a part of the Creo process.
The parts of the application that interact with the Creo session can be combination of Web.Link code that is executed in the browser and Creo.JS code that is executed in Creo. This enables you to gradually move your applications from Web.Link to Creo.JS. Since both parts of the application run in different processes they cannot exchange direct references to their runtime objects. They interact by passing JSON objects. All calls between environments are asynchronous. You must use programming patterns, such as, AJAX subscription style, or reactive development in Node.js, for distributed application development in JavaScript.
Use JavaScript promises in Creo.JS to work with callback functions.
Creo.JS supports all the Web.Link APIs. Similar to the Web.Link application, the Creo.JS application is sent to the embedded browser of Creo and does not require any additional components.
Installing Creo.JS
Creo.JS is available on the same CD as Creo Parametric. When Creo Parametric is installed using PTC.SetUp, one of the optional components is API Toolkits. This includes Creo.JS toolkit.
Creo.JS is installed when you install Web.Link. The following folders are installed for Creo.JS:
•  A directory called creojs is created at C:\Program Files\PTC\Creo 4.0\apps. This directory contains all the libraries and example applications specific to Creo.JS.
•  A directory called creojs is also created at C:\Program Files\PTC\Creo 4.0\Common Files\creojs. This directory contains documentation specific to Creo.JS. It contains an online browser called the Creo.JS APIWizard, which contains definitions for modules, classes, and methods. The Creo.JS User’s Guide in PDF format is also installed in this folder.
MIME Type for Webserver
The administrator can add all common scripts to the server instead of copying them to each user’s computer. In such a case, the folder creojsweb is located on your local server. If administrator is using IIS Webserver for adding common scripts, a custom defined MIME type *.creojs needs to be added to the Webserver IIS (Windows 7/10). You need to configure the server configuration file web.config as follows:

<configuration>
		<system.webServer>
				<staticContent>
						<mimeMap fileExtension=".creojs" mimeType="text/creojs" />
				</staticContent>
		</system.webServer>
</configuration>