A few days ago I installed the latest version of the Netbeans IDE (which is far better than Eclipse, by the way). Version 7.3.1 included code from so called Project Easel with support for HTML5 Application Development with the new following features: HTML5 Application project with Javascript testing support, improved Javascript editor, Page inspector and visual CSS style editor
Javascript Debugger, Embedded Webkit browser; deep integration with Chrome. The recently released Netbeans 7.4 added several new features on top of that:

  • Application development with Cordova (that is Phonegap)
  • Support for Android and iOS Browsers
  • Editing support for stylesheet languages SASS and LESS
  • Editing support for AngularJS, Knockout and ExtJS
  • Navigator and code folding for JSON files

I have installed it on my Mac and it works great. It has code completion for HTML tags including attributes and CSS styles. It does syntax checks on the HTML during editing and highlights missing tags.

The Netbeans IDE comes with included Webkit browser for previewing your HTML apps, but recommeds the use of the Chrome browser which is supported through a separate extension that connects the browser with the IDE. For mobile HTML5 Netbeans mode makes use of Chromes ability to resize itself to a size of a mobile screen.

Also, in case you didn’t know, the Chrome developer extension can emulate touch events.

Netbeans also has support for Java, PHP, XML and Groovy. Ruby support has been phased out apparently, Python is supported through a community extension.

If you are doing serious HTML5 development, be sure to give Netbeans 7.4 a try.