JScript

JScript is a proprietary dialect of the JavaScript scripting language developed by Microsoft. It is an implementation of the ECMAScript standard that extends JavaScript with Microsoft-specific features and hosting environments. JScript was designed to run in Microsoft environments such as Internet Explorer for client-side scripting and the Windows Script Host for script-driven automation. It also served as one of the scripting options for classic ASP pages.

Historically, JScript appeared in the mid-1990s as Microsoft’s counterpart to Netscape’s JavaScript. Over time, Microsoft released multiple versions of the JScript engine bundled with Internet Explorer and the Windows Script Host. In addition to the original JScript, Microsoft introduced JScript.NET, a separate variant that targets the .NET Framework. JScript.NET provides static typing and direct access to .NET libraries while retaining a JavaScript-like syntax.

In terms of compatibility and evolution, newer web engines such as Chakra in later versions of Internet Explorer and Edge, along with evolving web standards, reduced the prominence of JScript as a browser scripting language. JScript.NET remains mainly a niche within enterprise environments and automation scripts that run on .NET rather than in web browsers.

Current status and usage focus on legacy and specialized contexts. For web development, standard JavaScript is used across modern browsers, while Microsoft-era JScript features are largely of historical interest. JScript continues to appear in Windows Script Host scripts and in some classic ASP or enterprise automation scenarios, where legacy codebases still rely on Microsoft’s JavaScript dialect.