Editing JScript (section)

=== JScript "Chakra" (JsRT) ===
{{See also|Chakra (JScript engine)}}
JScript "Chakra" is based on the JScript (COM classic) version, but it has been redesigned to improve performance in [[Internet Explorer 9]]<ref>{{cite web |last1=Niyogi |first1=Shanku |title=The New JavaScript Engine in Internet Explorer 9 |url=https://docs.microsoft.com/en-us/archive/blogs/ie/the-new-javascript-engine-in-internet-explorer-9 |website=IEBlog (archives) |date=18 March 2010 |publisher=Microsoft |access-date=19 February 2020}}</ref> at the expense of proper Active Scripting engine compatibility. It requires a specific Microsoft JavaScript Hosting (JsRT) API for proper use. Therefore, it is installed side by side with JScript 5.x and is only used by [[Internet Explorer 9]] and later as well as JsRT hosts, while other Active Scripting hosts keep using the 5.x version when requesting the JScript engine.

{| class="wikitable" style="text-align: center;"
|-
! Version
! Date
! Introduced with<ref>{{citation |url=https://msdn.microsoft.com/en-us/library/s4esdbwz.aspx |title=Version Information (Windows Scripting – JScript) |publisher=Microsoft |access-date=2010-05-31}}</ref>
! Based on<ref>{{cite web |title=Internet Explorer Standards Support Documents |url=https://docs.microsoft.com/en-us/openspecs/ie_standards/ms-iestandlp/8aea05e3-8c1e-4a9a-9614-31f71e679459 |website=Open Specifications (Microsoft Docs) |publisher=Microsoft |access-date=19 February 2020 |language=en-us}}</ref>
! Similar [[JavaScript]] version
|-
| Chakra 9.0
| Mar 2011
| [[Internet Explorer 9|Internet Explorer 9.0]]
| ECMA-262 5th edition
| 1.8.1
|-
| Chakra 10.0
| Sep 2012
| [[Internet Explorer 10|Internet Explorer 10.0]]
| ECMA-262 5.1 edition
| 
|-
| Chakra 11.0
| Oct 2013
| [[Internet Explorer 11|Internet Explorer 11.0]]
| ECMA-262 6th edition
| 
|-
| Chakra Edge
| Jul 2015
| [[Microsoft Edge Legacy|Edge [Legacy]]] / [[Windows 10]]
| ECMA-262 5.1 to 9 (2018) edition
(kept up to date without engine versioning)
| 
|}

There are two versions of the Chakra JsRT engine.
The original one was used by [[Internet Explorer 9]] and later, and is sometimes referred to as "jscript9.dll" or "legacy Chakra engine", and a second one used by [[Microsoft Edge Legacy]] browser and sometimes referred to as "new Chakra engine", "Edge engine" or "Chakra.dll".
Both Chakra JsRT versions can be used by other applications using the JsRT API and can be installed side by side.<ref>{{cite web |title=Targeting Microsoft Edge vs. Legacy Engines in JsRT APIs |url=https://docs.microsoft.com/en-us/microsoft-edge/hosting/chakra-hosting/targeting-edge-vs-legacy-engines-in-jsrt-apis |website=Microsoft Edge documentation (Microsoft Docs) |publisher=Microsoft |access-date=19 February 2020 |language=en-us}}</ref>

There is also a [[#JScript_(COM_Classic)|COM Classic]] version of Chakra internally called "JScript 9 Legacy" (provided by jscript9Legacy.dll), introduced with Windows 11 24H2, which brings back compatibility with Active Scripting hosts and intended as a compatible drop-in replacement for JScript 5.8. Although largely compatible with the original JScript 5.8, there are notable breaking differences.<ref>{{cite web | url=https://learn.microsoft.com/en-us/answers/questions/1071647/windows-11-22h2-has-a-different-way-of-using-the-j | title=Windows 11 22H2 has a different way of using the JS engine? - Microsoft Q&A }}</ref>

See separate page about [[Chakra (JavaScript engine)|new Chakra (Edge) engine]].