ActionScript® is an object-oriented, full-fledged scripting language in which web developers can code scripts to achieve high-end animation and interactivity for web pages. It is the programming language behind Adobe® Flash®, software that is used not only to create animated and interactive web pages but also to create highly graphical, animated and "flashy" websites. When Flash® is used, it is not necessary to actually know the ActionScript® language, because of the graphical environment in which files are coded.
Animation, drop-down navigational menus, images that fade and reappear after a determined number of seconds have elapsed and website introductions are just some of the things that can be achieved using applications written in ActionScript®. Status bars or meters also can be designed in Flash® to show visitors the status of the loading of a web page. These applications can be coded "behind the scenes" within the Adobe® Flash® program or in external ActionScript® files, which can be coded in a simple text editing program. External ActionScript® documents can be loaded or imported into Flash® (.FLA) files if a developer so desires. This might even be necessary depending on the type of application being written and on the specific version of Flash® being used.
There are three file extensions related to ActionScript®: .FLA, .AS and .SWF. The Flash® program creates .FLA and .SWF files. The .FLA document is the source file which can be opened and edited in Flash® but it is not the file that actually plays in the Flash® player. Files ending in .SWF are those that the player handles, and they produce what users see whether they are watching a presentation or are visitors to a website that uses this scripting language. Documents ending in .AS are external files holding code written in ActionScript®.