See the below example to know your system resolution

package druva.vini {
  import flash.system.Capabilities;
  import flash.net.*;
  import flash.display.*;
  import flash.text.TextField;

  public class SystemCap extends Sprite {

    public function SystemCap(){
        var resX:int = flash.system.Capabilities.screenResolutionX;
        var resY:int = flash.system.Capabilities.screenResolutionY;

		var field:TextField = new TextField();
			field.border = true;
			field.text = 'resX ' + resX + '\nresY ' + resY;
			field.background = true;
			addChild(field);
    }
  }
}

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