Get varaible on main timeline into document class

programming flash
1

I have a new FLA with a variable in frame 1:


var testVar:String = "hello";

//--- my document class:
package
{
	import flash.display.*;

	public class Vforum extends MovieClip
	{
		
		public function Vforum()
		{
			super();
			if(this.stage)
			{
				this.stage.scaleMode = StageScaleMode.NO_SCALE;
				this.stage.align = StageAlign.TOP_LEFT;
			}
			trace(this.testVar); //not working!
		}

		
	}
	
}

I just get null. How can I see a variable like that?