Here are some free WYSIWYG HTML Editor software and online tools. You can edit the output content and HTML source code and preview it.

Version 7.0 of NetBeans integrated development environment (IDE) is now available for Mac OS X, Windows, Solaris, and Linux. This free, open-source tool supports development of desktop, enterprise, ...

ConstEdit is a free HTML5 editor that lets you create & edit HTML & HTML5 documents & web pages. This word processor comes with a rich editing toolset.