Key features include:

- Advanced work with CSS
- Setting indentation (margins, paddings) for images and table cells (seperate for each direction)
- Controlling border properties (width, style, color) with convenient dialogs
- Writing element properties as CSS-style always when possible
- Interface appearance is configured from one CSS file
- The editor can be easily localized into any language. Currently available in English (default), Russian, German and Ukrainian languages

CLEditor is:

- Lightweight: CLEditor consumes less than 10K of total bandwidth.

- Full Featured: In addition to the standard text formatting features found in other WYSIWYG editors, CLEditor also contains rich drop downs for font name, size, style, text color and highlight color. CLEditor allows you to insert images, hyperlinks and horizontal rules.

- Cross Browser: CLEditor supports the following browsers on both the mac and pc: IE 6.0+, FF 1.5+, Safari 4+, Chrome 5+ and Opera 10+. All testing is done using jQuery 1.4.2.

- Extensible: CLEditor provides a rich plugin development environment, allowing you to customize its user interface and functionality to fit your needs.

As well as features found in standard text editing components, Scintilla includes features especially useful when editing and debugging source code. These include support for syntax styling, error indicators, code completion and call tips. The selection margin can contain markers like those used in debuggers to indicate breakpoints and the current line. Styling choices are more open than with many editors, allowing the use of proportional fonts, bold and italics, multiple foreground and background colours and multiple fonts.

While jEdit beats many expensive development tools for features and ease of use, it is released as free software with full source code, provided under the terms of the GPL 2.0.

The jEdit core, together with a large collection of plugins is maintained by a world-wide developer team.

Some of jEdit’s features include:

* Written in Java, so it runs on Mac OS X, OS/2, Unix, VMS and Windows.

* Built-in macro language; extensible plugin architecture. Dozens of macros and plugins available.

* Plugins can be downloaded and installed from within jEdit using the “plugin manager” feature.

* Auto indent, and syntax highlighting for more than 130 languages.

* Supports a large number of character encodings including UTF8 and Unicode.

* Folding for selectively hiding regions of text.

Komodo Edit, based on the award-winning Komodo IDE, offers sophisticated support for all major scripting languages, including in-depth autocomplete and calltips, multi-language file support, syntax coloring and syntax checking, Vi emulation, Emacs key bindings.

The Firebug plugin YSlow is a web development tool and analyzes web pages and tells you why they’re slow based on the rules for high performance web sites. It offers

* Performance report card
* HTTP/HTML summary
* List of components in the page
* Tools including JSLint

It has all the advantages of an Cocoa application and some of its features are tabs, line numbers, support for syntax colouring for many different languages, functions list, support for text encodings, snippets, a toolbar, a status bar, preview, split window, multi-document find and replace with regular expressions, possibility to show invisible characters, authenticated open and saves, command-line utility, full screen editing and running commands and scripts from within the application.

The features of GNU Emacs include:

* Content-sensitive editing modes, including syntax coloring, for a wide variety of file types including plain text, source code, and HTML.

* Complete built-in documentation, including a tutorial for new users.

* Support for many languages and their scripts, including all the European “Latin” scripts, Russian, Greek, Japanese, Chinese, Korean, Thai, Vietnamese, Lao, Ethiopian, and some Indian scripts.

* Highly customizable, using Emacs Lisp code or a graphical customization interface.

* A large number of extensions that add other functionality, including a project planner, mail and news reader, debugger interface, calendar, and more. Many of these extensions are distributed with GNU Emacs; others are available separately.

The free version includes the core pieces of Aptana Studio’s editing, debugging, synchronization, and project management capabilities, including pieces for scripting, customizing and extending Aptana Studio.

There is also support for Adobe AIR, Apple iPhone, PHP, and Ruby on Rails development, which comes via additional development plugins – also free.