JavaScript is the name of Netscape Communications Corporation's and now the Mozilla Foundation's implementation of the ECMAScript standard, a scripting language based on the concept of prototype-based programming. The language is best known for its use in websites (as client-side JavaScript), but is also used to enable scripting access to objects embedded in other applications.

Despite the name, JavaScript is only distantly related to the Java programming language, the main similarity being the common debt to the C syntax. Semantically, JavaScript syntax has far more in common with the Self programming language.

JavaScript is a registered trademark of Sun Microsystems, Inc. It was used under license for technology invented and implemented by Netscape Communications and current entities such as the Mozilla Foundation.