Adobe Integrated Runtime (AIR) is a cross-operating system runtime environment for building rich Internet applications. AIR is intended to be a very versatile runtime environment, as it allows existing Flash or HTML and JavaScript code to be re-used to construct a more traditional desktop-like program. AIR applications can operate offline, and then activate further functionality or upload data when an active internet connection becomes available. Adobe AIR has a rich set of features, with support for building applications using HTML, JavaScript, Flex and Flash.