The SeaMonkey project is a community effort to develop an all-in-one Internet application suite. It contains an Internet browser, email and newsgroup client with an included Web feed reader, HTML editor, IRC chat, and Web development tools, and is sure to appeal to advanced users, Web developers, and corporate users. It uses much of the Mozilla source code powering such successful siblings as Firefox, Thunderbird, Camino, Sunbird, and Miro.
TEA is a powerful and easy-to-use Qt4-based editor with many useful features for HTML, Docbook, and LaTeX editing. It features a small footprint, a tabbed layout engine, support for multiple encodings, code snippets, templates, customizable hotkeys, an "open at cursor" function for HTML files and images, miscellaneous HTML tools, preview in external browser, string manipulation functions, Morse-code tools, bookmarks, syntax highlighting, and more.
PHPTAL is a fast, safe, XML-based template engine for XHTML and HTML5. It implements Zope's Template Attribute Language, which has clean, concise syntax that is compatible with XML tools (no custom ugly tags), and template source files can even be previewed in Web browsers or opened in WYSIWYG editors. Templates are compiled to PHP and cached, giving great performance and taking advantage of PHP accelerators. PHPTAL by default ensures well-formed output and escapes XML-unsafe characters everywhere, which means that your pages can be completely safe against HTML-injection (XSS) without great effort. It features fine-grained caching of output, pre- and post- filters, internationalization via gettext or custom backend, creation of custom template attributes and expressions, and templates loaded from non-standard sources (e.g. databases). It supports UTF-8 well, is easy to integrate and redistribute with PHP frameworks and applications, and has an object-oriented design and a comprehensive unit test suite.
elRTE is a WYSIWYG HTML editor for the Web written using jQuery. It features rich text editing, options for changing its appearance and style, insertion and management of various HTML elements with formatting (images, tables, lists, etc.), support for viewing and editing HTML code, and normal and full-screen modes.