Add/Subtract Items from an Array

package
{
	import flash.display.Sprite;
	import flash.events.MouseEvent;
	import fl.controls.TextArea;
 
	public class ArrayExample extends Sprite
	{
		private static var buttonOffset:Number = 141;
		private var _itemsArr:Array = ["Earth", "Fire", "Wind", "Water", "Chicken"];
		private var _activeItemArr:Array = new Array;
 
		private var container:Sprite;
		private var traceArea:TextArea;
		private var button:ButtonClass;
 
		public function ArrayExample()
		{
			buildDisplay();
			positionDisplay();
		}
 
		private function buildDisplay():void
		{
			container = new Sprite();
			addChild(container);
			container.addEventListener(MouseEvent.MOUSE_DOWN, buttonHandler);
 
			var buttonPosition:Number = 0;
			for(var i:uint = 0; i < _itemsArr.length; i++)
			{
				button = new ButtonClass();
				container.addChild(button);
				button.label = _itemsArr[i];
				button.x = buttonPosition;
				buttonPosition += buttonOffset;
			}
 
			traceArea = new TextArea();
			addChild(traceArea);
		}
 
		private function positionDisplay():void
		{
			traceArea.x = container.x;
			traceArea.y = container.y + 30;
			traceArea.width = container.width;
		}
 
		private function buttonHandler(e:MouseEvent):void
		{
			var activeItem:ButtonClass = e.target as ButtonClass;
 
			if(!activeItem.added){
				addToArray(e.target.label);
				activeItem.added = true;
			} else { 
				removeFromArray(e.target.label);
				activeItem.added = false;
			}
 
			traceArea.text = String(_activeItemArr);
		}
 
		private function addToArray(type:String)
		{
			var dupNumber:Number = 0;
			_activeItemArr.push(type);
 
			for (var i : int = 0; i < _activeItemArr.length; i++) {
				if (_activeItemArr[i] == type) dupNumber++;
			}
 
			if (dupNumber > 1) _activeItemArr.pop();
		}
 
		private function removeFromArray(type:String)
		{
			for (var i : int = 0; i < _activeItemArr.length; i++) {
				if (_activeItemArr[i] == type) _activeItemArr.splice(i,1);
			}
		}
 
 
	}
}

package
{
	import fl.controls.Button;
 
	public class ButtonClass extends Button
	{
		private var _added:Boolean = false;
 
		public function get added():Boolean
		{
			return _added;
		}
 
		public function set added(added:Boolean):void
		{
			_added = added;
		}
 
		public function ButtonClass(){}
 
	}
}