ECMAScript and JavaScript: The Relationship
ECMAScript is the international standard specification for the JavaScript language, while JavaScript is a specific implementation of the ECMAScript standard. In simple terms, ECMAScript defines the core rules of the language: syntax, types, statements, keywords, reserved words, operators, and objects. JavaScript (along with runtime environments like Node.js) is the actual, usable programming language built by following these rules.
Historical Background: From JavaScript to ECMAScript
In November 1996, Netscape, the creator of JavaScript, decided to submit JavaScript to the European Computer Manufacturers Association (ECMA, now Ecma International) to establish it as an international standard. The following year, ECMA published the first edition of standard document ECMA-262, formally standardizing the browser scripting language and naming this standardized language ECMAScript (version 1.0).
Why the Name ECMAScript and Not JavaScript?
This decision was primarily based on two reasons:
- Trademark Issues: "Java" was a registered trademark of Sun Microsystems (later acquired by Oracle). Under the licensing agreement at the time, only Netscape had the legal right to use the name "JavaScript," which they had also trademarked. To avoid legal disputes, the standards body chose a neutral name.
- Emphasizing Openness: Using "ECMAScript" aimed to show that the language standard was developed and maintained by an international organization (ECMA), not a single company like Netscape. This helped ensure the language's openness and neutrality, encouraging broader participation and adoption.
The Core Relationship: Standard vs. Implementation
The relationship can be summarized as: ECMAScript is the specification; JavaScript is an implementation. Besides JavaScript, other languages like ActionScript (for the Flash platform) have also been implementations of ECMAScript.
Note: In everyday development discussions, the term "JavaScript" is often used loosely to refer to any language following the ECMAScript standard, so the two terms are frequently used interchangeably. However, strictly speaking, JavaScript refers specifically to the implementation running in environments like browsers or Node.js.
Modern ECMAScript and the JavaScript Ecosystem
Today, the ECMAScript standard continues to evolve, with new versions released annually (e.g., ES2015/ES6, ES2016). JavaScript engines (like V8, SpiderMonkey, JavaScriptCore) are responsible for implementing these new features. The code developers write as "JavaScript" is, in fact, code that follows (or partially follows) the current ECMAScript standard.
Understanding this distinction helps with:
- Accurately tracing the origin of language features (e.g., knowing a feature is part of ES6).
- Handling compatibility issues across different environments (as engines may implement standards at different paces).
- Consulting the official ECMAScript specification for the most authoritative language definition.