ActionScript 2.0 Language Reference - Adobe Help and Support

addListener (Selection.addListener method)
public static addListener(listener:Object) : Void
Registers an object to receive keyboard focus change notifications. When the focus changes
(for example, whenever Selection.setFocus() is invoked), all listening objects registered
with addListener() have their onSetFocus method invoked. Multiple objects may listen for
focus change notifications. If the specified listener is already registered, no change occurs.
Availability: ActionScript 1.0; Flash Player 6
Parameters
listener:Object - A new object with an onSetFocus method.
Example
In the following example, you create two input text fields at runtime, setting the borders for
each text field to true. This code creates a new (generic) ActionScript object named
focusListener. This object defines for itself an onSetFocus property, to which it assigns a
function. The function takes two parameters: a reference to the text field that lost focus, and
one to the text field that gained focus. The function sets the border property of the text field
that lost focus to false, and sets the border property of the text field that gained focus to
true:
this.createTextField("one_txt", 99, 10, 10, 200, 20);
this.createTextField("two_txt", 100, 10, 50, 200, 20);
one_txt.border = true;
one_txt.type = "input";
two_txt.border = true;
two_txt.type = "input";
var focusListener:Object = new Object();
focusListener.onSetFocus = function(oldFocus_txt, newFocus_txt) {
oldFocus_txt.border = false;
newFocus_txt.border = true;
};
Selection.addListener(focusListener);
When you test the SWF file, try using Tab to move between the two text fields. Make sure
that you select Control > Disable Keyboard Shortcuts so you can change focus between the
two fields using Tab.
See also
setFocus (Selection.setFocus method)
Selection 1085