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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RAIL
RAIL, an acronym for Response, Animation, Idle, and Load, is a performance model originated by the Google Chrome team in 2015, focused on user experience and performance within the browser. The performance mantra of RAIL is "Focus on the user; the end goal isn't to make your site perform fast on any specific device, it's to make users happy." There are 4 stages of interaction: page load, idle, response to input, and scrolling and animation. In acronym order, the main tenets are:

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See also