Quanta Plus, originally called Quanta, is a web Integrated development environment (IDE) for HTML, XHTML, CSS, XML, PHP and any other XML-based languages or scripting languages. Quanta was licensed under GPL before the release of version 2.0 final.
Quanta is capable of both WYSIWYG design and handcoding. It features tag completion on the fly, tag editing through a dialog interface, script language variable auto-completion, project management, live preview, PHP debugger, CVS support, Subversion support (through external plugin).
Quanta is no longer being developed, but some of its features have been merged to its sister project KDevelop.