JScript
implementation of ECMAScript by Microsoft
JScript is Microsoft's legacy dialect of the ECMAScript standard that is used in Microsoft's Internet Explorer web browser and HTML Applications, and as a standalone Windows scripting language. It is proprietary software.
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. 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 10.0 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", leading Microsoft to add an option to disable it.
“JScript” enters the record as implementation of ECMAScript by Microsoft. Crown Archives preserves that source wording while asking what JScript, implementation and ECMAScript can confirm, complicate or overturn.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Apr 2, 2026. The linked authority identifier is Q553514. The Library of Congress control number is sh2005002739. 3 of 4 selected statements include explicit references; 2 carry qualifiers and 1 use preferred rank. The first chronological checks are 1996.
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This entry incorporates text from “JScript” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.