Mozilla Composer

Mozilla Composer is the free and open-source HTML editor and web authoring module of the Mozilla Application Suite (the predecessor to SeaMonkey). It is used to create and to edit web pages, e-mail, and text documents easily. It is compatible with Windows, macOS and Linux. Composer is a graphical WYSIWYG HTML editor. One also can view, write and edit HTML source code with Composer.
Linspire sponsored development of Nvu, a stand-alone version of Mozilla Composer which incorporates Cascading Style Sheets support and other improvements from software company Disruptive Innovations.
Daniel Glazman, the lead developer of Nvu, announced on September 15, 2006 that he had stopped official development on Nvu and that he was developing a successor as a Mozilla.org project. It is written from scratch and based on Mozilla trunk Gecko 1.9 and XULRunner. PHP and CSS would be supported. A community-driven fork, KompoZer, maintains Nvu codebase and fixes bugs until a successor to Nvu is released. Glazman's project is called BlueGriffon.
SeaMonkey, the community-driven successor to Mozilla Suite, includes an HTML editor named Composer that is developed from the Mozilla Composer code contained in the original Mozilla Suite.