Buttons are actually four-frame interactive movie clips. When you select the button behavior for a symbol, Flash creates a Timeline with four frames. The first three frames display the button’s three possible states; the fourth frame defines the active area of the button. The Timeline doesn’t actually play; it reacts to pointer movement and actions by jumping to the appropriate frame.

To make a button interactive, you place an instance of the button symbol on the Stage and assign actions to the instance. You must assign the actions to the instance of the button in the document, not to frames in the button’s Timeline.

Each frame in the Timeline of a button symbol has a specific function:

• The first frame is the Up state, representing the button whenever the pointer is not over the button.

• The second frame is the Over state, representing the button’s appearance when the pointer is over the button.

• The third frame is the Down state, representing the button’s appearance as it is clicked.

• The fourth frame is the Hit state, defining the area that responds to the mouse click. This area is invisible in the SWF file.

Create a button using a movie clip symbol or a button component. Using each type of button has advantages. Creating a button using a movie clip lets you add more frames to the button or add more complex animation. However, movie clip buttons have a larger file size than button symbols. Using a button component allows you to bind the button to other components, to share and display data in an application. Button components also include prebuilt features, such as accessibility support, and can be customized. Button components include the Button, RadioButton, and CheckBox. For more information, see Button component in ActionScript 2.0 Components Language Reference or Using the Button in Using ActionScript 3.0 Components.

For a text tutorial about buttons, see Add Button Navigation and Animation on the Flash Tutorials page at www.adobe.com/go/learn_fl_tutorials.