Actionscript 3.0 - Destionation-animation

var myTimer:Timer = new Timer(80);
myTimer.addEventListener(TimerEvent.TIMER, moveBall);
myTimer.start();

var speed:Number = 20;
var startX:Number = ball_mc.x;
var startY:Number = ball_mc.y;
var endX:Number = 400;
var endY:Number = 300;
var i:Number = 0;

function moveBall(event:Event):void
{
if(i < speed)
{
ball_mc.x += (endX - startX) / speed;
ball_mc.y += (endY - startY) / speed;
}
else
{
myTimer.stop();
}
i++;
}