This page summarizes ActionScript's key terms and concepts, presented in more detail in our textbook chapters 9-10.
- Variables
- Variables are containers that hold data. This data can be text, numbers, or true/false states. For example, your movie could check to see if a viewer was accessing it on a mobile telephone. If so, it might set a variable called "mobile" to "true."
- Instances and Instance Names
- You must name the instance of a symbol (accessed in the Properties panel) in order to control the instance's behavior with ActionScript.
- Properties
- These are special kinds of variables that belong to instances of a symbol. For example, an instance's "alpha" property makes it more or less transparent. You can change properties with ActionScript; changing "alpha" will make the instance appear or disappear.
- Functions and Methods
- These are reusable blocks of ActionScript code that perform actions like stopping the movie or muting its audio. Designers often write functions from scratch, but Flash also contains a large number of pre-written functions, so you can easily control common actions.
- Events, Event Handlers, and Event Listeners
- Events are things that happen while a movie is playing. "Event listeners" wait for a specific event to happen. When it does, they trigger an "event handler" that responds to it.
- Classes
- Classes are like rubber stamps. Instances are like the individual images you can make with that stamp. This should sound familiar, since we have already worked with three different classes: graphic symbols, button symbols, and movie clip symbols. Other, nonvisual classes work the same. They allow you to create instances of a master class of objects, and each instance shares the properties of its particular class.
- Conditional Statements
- These are basic building blocks of computer code. They allow you to program the movie to test for a particular condition and respond based on whether the condition is true or false. Continuing the example from the "variables" definition: your movie might check the variable "mobile" to see if it is "true." If so, it will shrink the height and width of the stage so the movie works better on a mobile-phone display. If "mobile" is "false," the movie will simply exit the conditional statement without changing anything.