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{{Short description|Implementation of ECMAScript by Microsoft}}{{Distinguish|JavaScript}}

factoids

| paradigm = Microsoft| latest_release_version = 9.0| latest_release_date = March 2011Dynamic typing>Dynamic, weak typing, duck typing>duck| implementations = Active Scripting, JScript .NET| dialects =| influenced by =| influenced =| operating system = Microsoft Windows| license =1=https://learn.microsoft.com/en-us/previous-versions/hbxc2t98(v=vs.85)}}}}JScript is Microsoft's legacyWEB, 2020-10-13, Disabling legacy scripting engine JScript in Internet Explorer,weblink 2021-11-15, TECHCOMMUNITY.MICROSOFT.COM, en, dialect of the ECMAScript standardWEB,weblink JScript (ECMAScript3), 24 October 2011, Msdn.microsoft.com, 2012-08-17, that is used in Microsoft's Internet Explorer web browser.JScript is implemented as an Active Scripting engine. This means that it can be "plugged in" to OLE Automation applications that support Active Scripting, such as Internet Explorer, Active Server Pages, and Windows Script Host.WEB,weblink What Is WSH?, 24 October 2011, Msdn.microsoft.com, 2012-08-17, It also means such applications can use multiple Active Scripting languages, e.g., JScript, VBScript or PerlScript.JScript was first supported in the Internet Explorer 3.0 browser released in August 1996. Its most recent version is JScript 9.0, included in Internet Explorer 9.JScript 10.0What is JScript 10.0? is a separate dialect, also known as JScript .NET, which adds several new features from the abandoned fourth edition of the ECMAScript standard. It must be compiled for .NET Framework version 2 or version 4, but static type annotations are optional.JScript has been criticized for being insecure and having multiple security bugs "exploited by nation-state actors",WEB, Cimpanu, Catalin, Microsoft adds option to disable JScript in Internet Explorer,weblink 2021-11-15, ZDNet, en, leading Microsoft to add an option to disable it.WEB, Option to disable JScript execution in Internet Explorer,weblink 2021-11-15, support.microsoft.com,

Comparison to JavaScript

As explained by Douglas Crockford in his talk titled The JavaScript Programming Language on YUI Theater, However, JScript supports conditional compilation, which allows a programmer to selectively execute code within block comments. This is an extension to the ECMAScript standard that is not supported in other JavaScript implementations, thus making the above statement not completely true, although conditional compilation is no longer supported in Internet Explorer 11 Standards mode.Other internal implementation differences between JavaScript and JScript, at some point in time, are noted on the Microsoft Developer Network (MSDN).WEB,weblink The World of JScript, JavaScript, ECMAScript, 15 August 2007, Blogs.msdn.microsoft.com, 2017-10-21, The default type value for the script element in Internet Explorer is JavaScript, while JScript was its alias.WEB,weblink script element, Msdn.microsoft.com, 2017-10-16, In an apparent transition from JScript to JavaScript, online, the Microsoft Edge Developer Guide refers to the Mozilla MDN web reference library as its definitive documentation.WEB,weblink Microsoft-Edge Dev-Guide, Docs.microsoft.com, 2017-10-18, As of October 2017, Microsoft MSDN pages for scripting in Internet Explorer are being redirected there as well.WEB,weblink Documenting the Web Together, 18 October 2017, Blogs.windows.com, 2017-10-18, This information may not include JScript specific objects, such as Enumerator, which are listed in the JavaScript language reference on Microsoft Docs.WEB,weblink Javascript Language Reference (Microsoft Docs), Docs.microsoft.com, 2017-10-18, Those provide additional features that are not included in the ECMA Standards, whether they are supported in the Edge browser or its predecessor.WEB,weblink JavaScript Objects (Microsoft Docs), Docs.microsoft.com, 2017-10-18,

Versions

JScript (COM Classic)

The original JScript is an Active Scripting engine. Like other Active Scripting languages, it is built on the COM/OLE Automation platform and provides scripting capabilities to host applications.This is the version used when hosting JScript inside a Web page displayed by Internet Explorer, in an HTML application before IE9, as well as in classic ASP, Windows Script Host scripts and other Automation environments.JScript is sometimes referred to as "classic JScript" or "Active Scripting JScript" to differentiate it from newer .NET-based versions.Some versions of JScript are available for multiple versions of Internet Explorer and Windows. For example, JScript 5.7 was introduced with Internet Explorer 7.0 and is also installed for Internet Explorer 6.0 with Windows XP Service Pack 3, while JScript 5.8 was introduced with Internet Explorer 8.0 and is also installed with Internet Explorer 6.0 on Windows Mobile 6.5.Microsoft's implementation of ECMAScript 5th Edition in Windows 8 Consumer Preview is called JavaScript and the corresponding Visual Studio 11 Express Beta includes a "completely new", full-featured JavaScript editor with IntelliSense enhancements for HTML5 and ECMAScript 5 syntax, "VSDOC" annotations for multiple overloads, simplified DOM configuration, brace matching, collapsible outlining and "go to definition".WEB,weblink What's New in ASP.NET 4.5 and Visual Web Developer 11 Beta: The Official Microsoft ASP.NET Site, 13 May 2022, WEB,weblink What's New for ASP.NET 4.5 and Web Development in Visual Studio 11 Beta, 12 May 2015, {| class="wikitable" style="text-align: center;"! Version! Date! Introduced with{{citation |url=https://msdn.microsoft.com/en-us/library/s4esdbwz.aspx |title=Version Information (Windows Scripting – JScript) |publisher=Microsoft |access-date=2010-05-31}}! Based on{{refn|JScript supports various features not specified in the ECMA standard,{{citation |url=https://msdn.microsoft.com/en-us/library/4tc5a343.aspx |title=Microsoft JScript Features – Non-ECMA (Windows Scripting – JScript) |publisher=Microsoft |access-date=2010-05-31}} as does JavaScript.|group=note}}! Similar JavaScript version| 1.0| Aug 1996Internet Explorer 3>Internet Explorer 3.0SpiderMonkey>Netscape JavaScript| 1.0| 2.0| Jan 1997Internet Information Services>Windows IIS 3.0| Netscape JavaScript| 1.1| 3.0| Oct 1997| Internet Explorer 4.0Microsoft said JScript 3.0 was "the first scripting language to fully conform to the ECMA-262 standard".{{citation title=Microsoft Embraces ECMA Internet Scripting Standard; Delivers Industry's First ECMA-Compliant Scripting Language, JScript 3.0, In Key Microsoft Products date=1997-06-30weblink>archive-date=2009-01-12}}|group=note}}| 1.3| 4.0| Microsoft Visual Studio>Visual Studio 6.0 (as part of Visual InterDev)| ECMA-262 1st edition| 1.3| 5.0| Mar 1999| Internet Explorer 5.0| ECMA-262 2nd edition| 1.4| 5.1|| Internet Explorer 5.01| ECMA-262 2nd edition| 1.4| 5.5| Jul 2000| Internet Explorer 5.5 & Windows CE 4.2| ECMA-262 3rd edition| 1.5| 5.6| Oct 2001Internet Explorer 6>Internet Explorer 6.0 & Windows CE 5.0| ECMA-262 3rd edition| 1.5| 5.7| Nov 2006Internet Explorer 7>Internet Explorer 7.0TITLE=JSCRIPT DEVIATIONS FROM ES3 WEBSITE=THE REGISTER ACCESS-DATE=9 FEBRUARY 2020, + ECMA-327 (ES-CP){{refndate=May 2010}}name=ES-CP}}| 1.5| 5.8| Mar 2009Internet Explorer 8>Internet Explorer 8.0 & Internet Explorer Mobile 6.0group=note|name=ES-CP}} + JSON (RFC 4627)| 1.5JScript is also available on Windows CE (included in Windows Mobile, optional in Windows Embedded CE). The Windows CE version lacks Active Debugging.

Managed JScript

Managed JScript is an implementation of JScript for the Dynamic Language Runtime, it is part of Microsoft's dynamic languages for .NET along with IronRuby, IronPython, and Dynamic Visual Basic.Unlike JScript .NET, which is less dynamic than the original JScript but provides CLS compatibility, Managed JScript is designed on top of the DLR and provides the features needed for scripting scenarios.While it is primarily designed to be used within Silverlight and ASP.NET at this time, it can also easily be embedded within any .NET application.(Source: JScript Blog, Jim Hugunin's Thinking Dynamic blog,Source: Blog of Jitu)Two builds of Managed JScript exist: one for the Desktop CLR and one for the Silverlight CoreCLR{| class="wikitable"! Version! Date! Introduced with! Based on! PlatformASP.NET Futures (July 2007 preview) >Common Language Runtime>CLR 2.0Silverlight>Microsoft Silverlight 1.1 Alpha (Sep 2007 refresh) ECMA-262 3rd edition CoreCLR 1.1Managed JScript is not supported in the .NET Compact Framework.(Source: files versions of Microsoft.JScript.Runtime.dll in ASP.NET Futures and Silverlight 1.1 folders)

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 9WEB, Niyogi, Shanku, The New JavaScript Engine in Internet Explorer 9,weblink IEBlog (archives), 18 March 2010, Microsoft, 19 February 2020, 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{{citation |url=https://msdn.microsoft.com/en-us/library/s4esdbwz.aspx |title=Version Information (Windows Scripting – JScript) |publisher=Microsoft |access-date=2010-05-31}}! Based onWEB, Internet Explorer Standards Support Documents,weblink Open Specifications (Microsoft Docs), Microsoft, 19 February 2020, en-us, ! Similar JavaScript version| Chakra 9.0| Mar 2011Internet Explorer 9>Internet Explorer 9.0| ECMA-262 5th edition| 1.8.1| Chakra 10.0| Sep 2012Internet Explorer 10>Internet Explorer 10.0| ECMA-262 5.1 edition| | Chakra 11.0| Oct 2013Internet Explorer 11>Internet Explorer 11.0| ECMA-262 6th edition| | Chakra Edge| Jul 2015Microsoft Edge>Edge / Windows 10| ECMA-262 5.1 to 9 (2018) edition(kept up to date without engine versioning)| There are two versions of the Chakra engine, the original one used by Internet Explorer 9 and later, and sometimes referred to as "jscript9.dll" or "legacy Chakra engine", and a second one used by Microsoft Edge browser and sometimes referred to as "new Chakra engine", "Edge engine" or "Chakra.dll".Both Chakra versions can be used by other applications using the JsRT API and can be installed side by side.WEB, Targeting Microsoft Edge vs. Legacy Engines in JsRT APIs,weblink Microsoft Edge documentation (Microsoft Docs), Microsoft, 19 February 2020, en-us, See separate page about new Chakra (Edge) engine.

JScript .NET (CLI)

JScript .NET is a Microsoft .NET implementation of JScript. It is a CLI language and thus inherits very powerful features, but lacks many features of the original JScript language, making it inappropriate for many scripting scenarios.JScript .NET can be used for ASP.NET pages and for complete .NET applications, but the lack of support for this language in Microsoft Visual Studio places it more as an upgrade path for classic ASP using classic JScript than as a new first-class language.{| class="wikitable" style="text-align: center;"! Version! Platform! Date! Introduced with! Based onCommon Language Runtime>CLR 1.0 2002-01-05 Microsoft .NET Framework 1.0 ECMA-262 3rd edition{{refnurl=https://msdn.microsoft.com/en-us/library/xkx7dfw1(VS.71).aspx publisher=Microsoft}}name=dotnet}}Common Language Runtime>CLR 1.1 2003-04-01 Microsoft .NET Framework 1.1 ECMA-262 3rd editionCommon Language Runtime>CLR 2.0 2005-11-07 Microsoft .NET Framework 2.0 ECMA-262 3rd editionCommon Language Runtime>CLR 4.0 2010-08-03 Microsoft .NET Framework 4.0 ECMA-262 3rd editionJScript .NET is not supported in the .NET Compact Framework.{{citation needed|date=March 2012}}Note: JScript .NET versions are not related to classic JScript versions. JScript .NET is a separate product. Even though JScript .NET is not supported within the Visual Studio IDE, its versions are in sync with other .NET languages versions (C#, VB.NET, VC++) that follow their corresponding Visual Studio versions..NET Framework 3.0 and 3.5 are built on top of 2.0 and do not include the newer JScript.NET release (version 10.0 for .NET Framework 4.0).(Source: file version of jsc.exe JScript.NET compiler and Microsoft.JScript.dll installed with .NET Framework)

See also

• JScript.Encode
• Windows Script File
• Windows Script Host
• WinJS

Notes

{{Reflist | group=note}}

References

{{Reflist}}

External links

• JScript documentation in the MSDN Library
• JScript 5.7 Release Notes
• JScript .NET documentation in the MSDN Library
• JScript blog
• JavaScript – JScript – ECMAScript version history
• JScript Features – ECMA
• JScript Features – Non-ECMA
• New features in JavaScript (Microsoft Docs)

{{ECMAScript}}{{Microsoft APIs}}{{Internet Explorer}}{{Windows Components}}{{Authority control}}