ECMAScript (/ˈɛkməskrɪpt/; ES)[1] is a standard for scripting languages, including JavaScript, JScript, and ActionScript.
ECMAScript is commonly used for client-side scripting on the World Wide Web, and it is increasingly being used for server-side applications and services using runtime environments such as Node.js,[3] Deno[4] and Bun.
[6] ECMA-262 specifies only language syntax and the semantics of the core application programming interface (API), such as Array, Function, and globalThis, while valid implementations of JavaScript add their own functionality such as input/output and file system handling.
[7] In December 1995, Sun Microsystems and Netscape announced JavaScript in a press release.
Eich commented that "ECMAScript was always an unwanted trade name that sounds like a skin disease.
"[10] ECMAScript has been formalized through operational semantics by work at Stanford University and the Department of Computing, Imperial College London for security analysis and standardization.
[14] The ECMAScript language includes structured, dynamic, functional, and prototype-based features.
Transpiling adds an extra step to the build process and is sometimes done to avoid needing polyfills.
Instead, transpiling rewrites the ECMA code itself during the build phase of development before it reaches the interpreter.
The table below shows the conformance rate for current versions of software with respect to the most recent editions of ECMAScript.