ActionScript 2.0 Language Reference

Global Properties

Global properties are available in every script, and are visible to every Timeline and scope in your document. For example, global properties allow access to the timelines of other loaded movie clips, both relative (_parent) and absolute (_root). They also let you restrict (this) or expand (super) scope. And, you can use global properties to adjust runtime settings like screen reader accessibility, playback quality, and sound buffer size.

_accProps Property

_accProps.propertyName
instanceName._accProps.propertyName

For information on the Accessibility panel, see "The Flash Accessibility panel" in Using Flash.

To determine whether the player is running in an environment that supports accessibility aids, use the System.capabilities.hasAccessibility property .

The following table lists the name and data type of each _accProps property , its equivalent setting in the Accessibility panel, and the kinds of objects to which the property can be applied. The term inverse logic means that the property setting is the inverse of the corresponding setting in the Accessibility panel. For example, setting the silent property to true is equivalent to deselecting the Make Movie Accessible or Make Object Accessible option.

To refer to the _accProps object that represents the entire Flash document, omit the instanceName parameter. The value of _accProps must be an object. This means that if no _accProps object already exists, you must create one, as shown in the following example, before you can assign values to the properties of the _accProps object:

When _accProps is used without the instanceName parameter, changes made to _accProps properties apply to the whole SWF file. For example, the following code sets the Accessibility name property for the whole SWF file to the string "Pet Store" and then calls Accessibility.updateProperties() to cause that change:

In contrast, the following code sets the name property for a movie clip with the instance name price_mc to the string "Price":

If you are specifying several accessibility properties, make as many changes as you can before calling Accessibility.updateProperties(), instead of calling it after each property statement, as shown in the following example:

my_mc.gotoAndStop(2);

if (my_mc._accProps == undefined ) {
    my_mc._accProps = new Object();
}

my_mc._accProps.name = "Photo of Mount Rushmore";
Accessibility.updateProperties();

See also
    Accessibility.isActive(), Accessibility.updateProperties(), System.capabilities.hasAccessibility

_focusrect Property

If the global _focusrect property is set to false, then the default behavior for all buttons and movieclips is that keyboard navigation is limited to the Tab key. All other keys, including the Enter and arrow keys, are ignored. To restore full keyboard navigation, you must set _focusrect to true. To restore full keyboard functionality for a specific button or movieclip, you can override this global property using either Button._focusrect or MovieClip._focusrect.

Note: If you use a component, then FocusManager overrides Flash Player's focus handling, including use of this global property.

_focusrect = false;

See also
    Button._focusrect, MovieClip._focusrect

_global Property

Note: When setting the value of a global variable, you must use the fully qualified name of the variable, e.g. _global.variableName. Failure to do so will create a local variable of the same name that obscures the global variable you are attempting to set.

Returns
A reference to the global object that holds the core ActionScript classes, such as String, Object, Math, and Array.

_global.factorial = function(n:Number) {
    if(n <= 1) {
        return 1;
    } 
    else {
        return n * factorial(n - 1);
    }
}

trace(factorial(1)); // 1
trace(factorial(2)); // 2
trace(factorial(3)); // 6
trace(factorial(4)); // 24

The following example shows how the failure to use the fully qualified variable name when setting the value of a global variable leads to unexpected results:

_global.myVar = "globalVariable";
trace(_global.myVar);    // globalVariable
trace(myVar);        // globalVariable

myVar = "localVariable";
trace(_global.myVar);    // globalVariable
trace(myVar);        // localVariable

See also
    var statement, set variable statement

_highquality Property

Deprecated as of Flash Player 5 — This property was deprecated in favor of _quality.

See also
    _quality

_level Property

The initial SWF file loaded into an instance of the Flash Player is automatically loaded into _level0. The SWF file in _level0 sets the frame rate, background color, and frame size for all subsequently loaded SWF files. SWF files are then stacked in higher-numbered levels above the SWF file in _level0.

You must assign a level to each SWF file that you load into the Flash Player using loadMovieNum(). You can assign levels in any order. If you assign a level that already contains a SWF file (including _level0), the SWF file at that level is unloaded and replaced by the new SWF file.

loadMovieNum("sub.swf", 9);
myBtn_btn.onRelease = function() {
    _level9.stop();
};

You could replace _level9.stop() in the previous example with the following code:

_level9.gotoAndStop(5);

This action sends the playhead in the main Timeline of the SWF file in _level9 to Frame 5 instead of stopping the playhead.

See also
    loadMovie() function, MovieClip.swapDepths()

maxscroll Property

Deprecated as of Flash Player 5 — This property was deprecated in favor of TextField.maxscroll.

See also
    TextField.maxscroll, TextField.scroll

_parent Property

_parent.property
_parent._parent.property

this.square_mc.circle_mc.onRelease = function() {
    this._parent._alpha -= 5;
};

See also
    _root, targetPath() function

_quality Property

The _quality property can be set to the values described in the following table.

_quality = "LOW";

_root Property

_root.movieClip
_root.action
_root.property

Specifying _root is the same as using the deprecated slash notation (/) to specify an absolute path within the current level.

Note: If a movie clip that contains _root is loaded into another movie clip, _root refers to the Timeline of the loading movie clip, not the Timeline that contains _root. If you want to ensure that _root refers to the Timeline of the loaded movie clip even if it is loaded into another movie clip, use MovieClip._lockroot.

_root.stop();

for (prop in _root) {
    trace("_root."+prop+" = "+_root[prop]);
}

See also
    MovieClip._lockroot, _parent, targetPath()

scroll Property

Deprecated as of Flash Player 5 — This property was deprecated in favor of TextField.scroll.

    
    on (release) {
        myText.scroll = myText.scroll + 1;
    }
    

See also
    TextField.maxscroll, TextField.scroll

_soundbuftime Property

_soundbuftime:Number = integer

// create text fields to hold debug information.
this.createTextField("counter_txt", this.getNextHighestDepth(), 0, 0, 100, 22);
this.createTextField("debug_txt", this.getNextHighestDepth(), 0, 20, 100, 22);
// set the sound buffer to 10 seconds.
_soundbuftime = 10;
// create the new sound object instance.
var bg_sound:Sound = new Sound();
// load the MP3 sound file and set streaming to true.
bg_sound.loadSound("yourSound.mp3", true);
// function is triggered when the song finishes loading.
bg_sound.onLoad = function() {
    debug_txt.text = "sound loaded";
};
debug_txt.text = "sound init";
function updateCounter() {
    counter_txt.text++;
}
counter_txt.text = 0;
setInterval(updateCounter, 1000);

this Property

Because this is evaluated in the context of the script that contains it, you can't use this in a script to refer to a variable defined in a class file.

class ApplyThis {
    var str:String = "Defined in ApplyThis.as";
    function conctStr(x:String):String {
        return x+x;
    }
    function addStr():String {
        return str;
    }
}

Then, in a FLA or a separate ActionScript file, add the following code

var obj:ApplyThis = new ApplyThis();
var abj:ApplyThis = new ApplyThis();
abj.str = "defined in FLA or AS";
trace(obj.addStr.call(abj, null));  //output: defined in FLA or AS
trace(obj.addStr.call(this, null));  //output: undefined
trace(obj.addStr.call(obj, null));  //output: Defined in applyThis.as

Similarly, to call a function defined in a dynamic class, you must use this to invoke the function in the proper scope:

// incorrect version of Simple.as
/*
dynamic class Simple {
    function callfunc() {
        trace(func());
    }
}
*/
// correct version of Simple.as
dynamic class simple {
    function callfunc() {
        trace(this.func());
    }
}

Inside the FLA or a separate ActionScript file, add the following code:

var obj:Simple = new Simple();
obj.num = 0;
obj.func = function() {
    return true;
};
obj.callfunc();
// output: true

The above code works when you use this in the callfunc() method. However you would get a syntax error if you used the incorrect version of Simple.as, which was commented out in the above example.

function Circle(radius:Number):Void {
    this.radius = radius;
    this.area = Math.PI*Math.pow(radius, 2);
}
var myCircle = new Circle(4);
trace(myCircle.area);

// sets the alpha property of the current movie clip to 20
this._alpha = 20;

In the following statement inside a MovieClip.onPress handler, the keyword this references the current movie clip:

this.square_mc.onPress = function() {
    startDrag(this);
};
this.square_mc.onRelease = function() {
    stopDrag();
};

See also
    on() function, onClipEvent() function