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®.
Created by Mr. Gary Grossman, ActionScript® bears similarities to JavaScript, another scripting language widely used in front-end web development, and to Java, a full-fledged programming language based on C. Not all Flash® developers take the time to learn the ActionScript® language, but those who code applications that utilize classes and subclasses do learn it. The language was developed to be easy to learn and powerful and to be used to write applications to play in a cross-browser platform — Flash®. Some web developers, however, avoid using the language because they must rely on the free, but proprietary, player to test scripts and because not all versions of the player are trouble-free on all browsers.