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JScript Language Reference

NodeJS vs JScript

Default JS engine for Rapise is Microsoft JScript with WScript runtime. This document contains language reference for this version.

Since Rapise 6.7 there is an alternative JavaScript runtime - NodeJS v14.15.3. As for 6.7 it is an experimental feature that you may enable either for single test project or globally.

NodeJS Support Features and Limitations

As of Rapise 6.7 NodeJS support is still experimental and default engine is still JScript/WScript. However the plan is to make NodeJS the default in the future.

Switching to NodeJS is safe in most of the cases - older tests should just work on new JS runtime without any noticeable differences.

The engine is defined in two places:

  1. In the Test Settings (one of Default, Node, WScript). Where Default means use engine defined in the Global Options.
  2. In Global Options (one of Default, Node, WScript). Where Default means WScript, but in the future it will be Node.


  1. NodeJS v14 contains most of latest features of JavaScript including EcmaScript2015 (ES6) and beyond. You may see more detailed list of features here.
  2. You may find the most complete and up to date language reference at
  3. You may use most of available npm packages in your test scripts. You may include node_modules folders in the root of your testing framework (i.e. %WORKDIR%\node_modules).


  1. Rapise IDE and JavaScript editor contains lots of features for comfortable JavaScript editing. This part is now tailored for JScript/WScript and may show false negative behavior. It may show warnings during editing because some syntax is not JScript compatible (although it is fine for Node/ES6). I.e. the following language features are not understood by the parser and may show a warning that you need to just ignore:

    • let, const keywords
    • ()=>lambda function definitions
    • (...args)
    • {parts,of,obj} = someobj
    • obj = {field, defs}
    • '`' strings
    • class support
    • getters, setters
    • object methods.
  2. NodeJS engine now runs in 32 bit mode. This is required to keep compatibility with ActiveXObject support that is an essential part of WScript but has to be emulated in NodeJS.

  3. Rapise has own copy of node.exe installed. So if you have npm modules installed globally and need to use them in your test, you have to install them locally into the framework.

  4. npm is not installed with Rapise. So if you want ot use it, you need to have one installed separately.


The language reference covers EcmaScript v2 supported by default JScript Engine. It is missing majority of latest features, properties and methods. For example, there is no Array.join or String.trim.

  • Feature Information
  • Microsoft JScript Features - ECMA
  • Microsoft JScript Features - Non-ECMA
  • Errors
  • Functions
  • Methods A-C

    Methods D-F

    Methods G

    Methods I-M

    Methods P-R

    Methods S

    Methods T-V





    JScript Fundamentals

    Advanced JScript

    Introduction to Regular Expressions