Netbeans IDE 7.3 has been released which adds powerful support for HMTL5 with automatic code completion elements for HTML5 called Project Easel. NetBeans IDE 7.3 gives a great facilities for  developers to create and debug rich web and mobile applications using the latest HTML5, JavaScript, and CSS3 standards. Developing rich web application is easier with a page inspector and CSS style editor, completely improved JavaScript editor, new JavaScript debugger, and more.

Below are some Netbeans 7.3 changes and improvements related to web application development (server side and client side) :
  • HTML5 Application project with JavaScript testing support
  • JavaScript Editor significantly improved
  • Page inspector and visual CSS style editor
  • JavaScript Debugger
  • Embedded WebKit browser; deep integration with Chrome
  • Parsers for Namespaced Annotations (Symfony 2, Doctrine 2, etc.)
  • Basic Composer Integration (Dependency Manager for PHP)
  • Twig Code Completion (with documentation)
  • Smarty Braces Matching for Related Tags
  • Smarty Parser Errors of Unmatched Tags
Install Netbeans 7.3 on Ubuntu
As far as I know, there is no Netbeans package on Ubuntu. So, you have to download Netbeans 7.3 installer from its website. Don't worry, Netbeans installer comes with GUI installation wizard, so you won't find any difficulties on installing it. Please download Netbeans 7.3 installer here. Once downloaded run the following command to start the installation wizard.
  • sh
Netbeans 7.3 installation wizard will start, all you need to do is follow on-screen instruction to get everything done.

Sit back and relax while the wizard install Netbeans 7.3 on your computer. Netbeans 7.3 can import settings from older version of Netbeans including project listings, application settings, and installed plugins. So there is no need to worry about reinstall all plugins or find your projects one by one.

Regards :)