scrolling background across

//set up variables.

var blockArray:Array = new Array();

var bGspeed:Number = 6

var gameover:Boolean = true;

var BgLeft:Boolean = false;

var BgRight:Boolean = false;

// set up and run a game control function.

stage.addEventListener(Event.ENTER_FRAME, gameControl);

function gameControl(myevent:Event):void

{

            if (BgLeft == true)

            {

                       

                        if (bGround.x  <-((bGround.width/2)-bGspeed))

                        {

                                    bGround.x = 0;

                        }

                        else

                        {

                                    bGround.x -=  bGspeed;

                        }

            }

            if (BgRight == true)

            {

                        if (bGround.x >= 0)

                        {

                                    bGround.x = -( bGround.width/2)+bGspeed;

                        }

                        else

                        {

                                    bGround.x +=  bGspeed;

                        }

            }

           

}

// listen to keyboard being pressed.

stage.addEventListener(KeyboardEvent.KEY_DOWN, moveBg);

stage.addEventListener(KeyboardEvent.KEY_UP, stopBg);

// if not pressed set move bGround to false.

function stopBg(myevent:KeyboardEvent):void

{

            if (myevent.keyCode == Keyboard.RIGHT)

            {

                        BgRight = false;

            }

            if (myevent.keyCode == Keyboard.LEFT)

            {

                        BgLeft = false;

            }

}

// if pressed set move bGround to true.

function moveBg(myevent:KeyboardEvent):void

{

            if (myevent.keyCode == Keyboard.RIGHT)

            {

                        BgRight = true;

            }

            if (myevent.keyCode == Keyboard.LEFT)

            {

                        BgLeft = true;

            }

}