An open-source, browser-based plain text editor built entirely with HTML, CSS and JavaScript:

http://browserpad.org

Browserpad will always be a plaintext editor: no Markdown/HTML preview, no WYSIWIG, no rich text editing. Think a browser-based notepad with a few extra text manipulation features. The aim of this guiding principle is to prevent feature creep and keep the tool focused, the Unix way: do one thing, and do it well.

• Browserpad started up as a very simple browser notepad entirely contained in a data URI: data:text/html,<textarea autofocus style='width:100%;height:100%;border:none;outline:none'/> (try copying and pasting that to your browser address bar and pressing enter). This concept was originally decribed by @jjperezaguinaga on his 4 Dec 2012 post "One line browser notepad".
  • Actually, it appears that it had been previously uncovered by @tabatkins, as evidenced by this 29 Jan 2012 tweet by @paulirish.
  • This 9 December 2011 Hacker News comment by @bytex64 mentions a talk about HTML5 where this was presented
  • @tabatkins and @bytex64 might have further info. It would be nice to get this documented.
• The data URI approach was neat, but impractical, and was eventually abandoned in favor of the regular HTML file approach.
• Browserpad is heavily inspired by the existing (but proprietary) online plaintext editors:
  • mytextarea.com
  • editpad.org
• In terms of features, Browserpad aims to match most of the text manipulation operations listed/implemented in:
  • textmechanic.com
  • textop.us (defunct)
  • wikipedia

Note: As a rule of thumb, Browserpad aims to support only editing operations that are generic and content-agnostic. This means it won't implement any context-sensitive functions that depend on the semantic meaning of the text, such as bracket matching, code linting, etc.

• support tab key
• auto-save using localStorage (see here)
• show statistics (lines/words/characters)
• indent-deindent (with Tab / Shift+Tab)
• keep selection visible (greyed out) when unfocused (see here)
• use contents of first line (or filename, if defined) as title (see here)
• menu entries (menu icon: ≡)
  • contrast (normal / night mode). (see icon here)
  • permalink / share (via data url)
  • save to a file (using the download attribute of the a element; browser support for the download attribute)
    • save as (custom filename).
  • load from a file on disk (based on this implementation)
  • show visual guide at: 0/72/80 CPL (radio buttons)
    • soft-wrap lines at specified CPL (need to wait for FF 36)
  • highlight current line
  • text operations (on whole text or selection):
    • case change (lower/upper/title)
    • search & replace
      • match highlight, emphasize current match, and cycling with F3
      • one-by-one or bulk replace
      • regex support
    • wrap-unwrap lines

• smart tabs-to-spaces conversion
• sync across machines (see issue #5)
• split window (different views of the same document (or maybe two separate documents?...)
• More inspiration from: ACE, CodeMirror, EditArea, more...

Browserpad is open source software released under the ISC License.