Foreword

ActionScript's beginnings can be traced to a bullet point titled "Enhanced Interactivity" on a Flash 4 feature planning list. Flash 3 offered a basic suite of actions to control Flash's movie clips and buttons and provide interactivity. However, I recall being impressed by a tic-tac-toe game, which, although a straightforward task in most programming languages, was difficult and time-consuming to implement using Flash 3 actions.

That was before ActionScript came into being. Today, one doesn't blink when encountering dynamic web sites created solely in Flash 4. And now, sites are appearing that exploit the even more sophisticated ActionScript capabilities of Flash 5.

A key goal of ActionScript was approachability; it was vital that ActionScript be easy to use for non-programmers. Rather than present a blank script-editing window, we created a visual, easily understandable interface in Flash 4 for adding interactivity to Flash movies. The simplicity of Flash 4 ActionScript made it easy to learn and kept the Flash Player small, a vital consideration.

The Flash Player is crafted to download quickly even over low-bandwidth connections. The Flash team repeats the mantra, "How much code will this add to the Player?" before adding any feature to it. ActionScript was no exception to this rule. The goal with ActionScript, as with every new Player feature, is maximum bang (feature richness) for minimum bucks (Player size increase).

We knew that users would put ActionScript to unforeseen uses, but all the same, it was a joyous shock to see what users were able to achieve with it. Within a month of the release of Flash 4, amazing sites employing ActionScript were appearing on the Web -- e-commerce sites, chat rooms, message boards, arcade games, board games, and even Flash sites to create Flash sites. The floodgates had been opened, bringing forth a new breed of animated, interactive, highly graphical web content.

The requirements of approachability and minimizing Player size remained tantamount. JavaScript is a subtle and complex language, and we sought to expose its full power to advanced users while retaining the ease of use of Flash 4 ActionScript. To this end, the new Flash 5 Actions panel has two modes: Normal Mode, a streamlined version of the Flash 4 ActionScript editor, and Expert Mode, a straight-ahead text editor for power users. To minimize Player size, sacrifices had to be made in the ECMAScript-compatibility of ActionScript. For example, ActionScript does not support compiling code at runtime using eval( ) ; this feature would have required the incorporation of the entire ActionScript compiler into the Player, resulting in an unacceptable size increase. For the same reason, regular expression matching is not supported. Both of these features are very useful and demonstrate the difficult decisions the Flash team was forced to make to balance the competing needs of Player size and features.