JScript
JScript is a Microsoft scripting language based on the ECMAScript standard, primarily used for client-side web scripting in Internet Explorer and server-side scripting in Active Server Pages (ASP). It is similar to JavaScript but includes Microsoft-specific extensions and integrates with Windows environments, such as Windows Script Host for automation tasks. JScript was a key component in early web development for Internet Explorer and Microsoft's server technologies.
Developers should learn JScript for maintaining legacy web applications built for Internet Explorer or ASP-based systems, as it was widely used in the late 1990s and early 2000s. It is also useful for Windows automation scripts using Windows Script Host, where it can interact with COM objects and system resources. However, for modern web development, it has largely been superseded by standardized JavaScript and newer frameworks.