MDN Web Docs Glossary: Definitions of Web-related terms

Web technologies contain long lists of jargon and abbreviations that are used in documentation and coding. This glossary provides definitions of words and abbreviations you need to know to successfully understand and build for the web.

Note: If you'd prefer a web development glossary in book form, check out The Web Development Glossary (EPUB, MOBI, PDF). It’s a third-party glossary that includes the entries found here, and also adds a wide range of additional entries.

Glossary of Terms

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Nullish value
In JavaScript, a nullish value is the value which is either null or undefined. Nullish values are always falsy.

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See also