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An improved JavaScript mode for GNU Emacs that emulates many desirable features of IDEs.

You can download it here.


  • Variable (adjustable) indentation
  • Accurate syntax highlighting
  • Highlighting of syntactic errors and many semantic errors
  • Strict-mode warning reporting (such as duplicate var declaration)
  • Smart line-wrapping in comments and strings
  • Typing helpers (e.g. matching quotes/brackets)
  • Code-folding (collapse element as {...})
  • Supports JavaScript 1.5, 1.6 (including E4X), 1.7 and 1.8
  • Customizable colors, or use font-lock defaults
  • Many customization options

Note - this mode is for GNU Emacs, version 22 and higher. It does not support XEmacs.

js2-mode was written by Steve Yegge. You can find more information on js2-mode at the official website: