Introducing Adobe AIR AIR application files are essentially “static” web application files packaged up for distribution. An end user installs the AIR runtime, just like the Flash runtime, and can then open up .air files containing HTML pages, CSS sheets and other resources. However, AIR applications are effectively “installed” to the end user's computer – Adobe AIR provides a standard installation dialog, and HTML resources inside an .air application file are then extracted to a folder on the user's computer (e.g. %PROGRAMFILES%\MyAIRApp under Windows). As developers, we then build web application using JavaScript on steroids – AIR runs a Webkit-based browser with excellent support for XHTML, CSS and JavaScript, and provides various operating system APIs through JavaScript. For example, AIR developers can use JavaScript to create native menus and system tray / dock icons.