According Bill Pataky, Oracle vice president of product management of tools and frameworks, the new release:
"allows developers to use the same IDE [to compose in] HTML5 that they would use for building back-end services that their Web and mobile applications would connect to."
The improvements in the new release aren't restricted to web and mobile. It also improves support for the Java platform with new hints and refactorings in the editor and improved support for editing FXML layout files in JavaFX projects. NetBeans IDE 7.3 continues to support the latest (Java EE) and GlassFish Server releases with the ability to run and test JPQL queries directly from the IDE.
The list of new features include:
Code completion for new HTML5 elements
Code completion support for jQuery
Support for responsive Web design-based applications
CSS Styling support and code completion for new CSS3 rules
Live code and Web page synchronization facilitated by deep bi-directional integration with Google Chrome and the internal WebKit-based browser.
Enhanced editor, with additional new features such as Breadcrumbs support and access to Clipboard History.
New support for profiling Java applications on Linux ARM based systems, such as the Raspberry Pi.
If you want more, this video highlights what's new in the release:
All that is missing at the moment is a drag-and-drop editor for HTML similar to the one used for Java Swing. With this addition NetBeans would be the total HTML package.