It's strange that, as Eclipse's "big" Ide doesn't bring its own HTML editor, so I foundEclipse HTML editor plugin .
Http://amateras.sourceforge.jp/cgi-bin/fswiki_en/wiki.cgi? Page = eclipsehtmleditor
Follow official steps to install GEF (Graphical editing framework)
Use the eclipse update Manager
1. Go to the help/software updates/find and install ..."
2. Choose the "search for new features to install" option
3. Add one of the update sites below.
Release site: http://download.eclipse.org/tools/gef/update-site/releases/site.xml
Milestone site: http://download.eclipse.org/tools/gef/update-site/milestones/site.xml
Update site for integration builds: http://download.eclipse.org/tools/gef/update-site/integrations/site.xml
After installing GEF, you can download eclipsehtmleditor. Put the downloaded JAR file in the/usr/lib/Eclipse/plugins/directory and restart it. Then you can directly edit HTML in eclipse.