max = 10;
speed = 0;

onEnterFrame = function() {
with(car) {
posX = Math.cos (angle); //這裡的圓的計算可以參考flash8的教學
posY = Math.sin (angle);

if (Key.isDown(key.left) && speed != 0) degree -= 5; //按左鍵角度-5
if (Key.isDown(key.right) && speed != 0)degree += 5;
if (Key.isDown(key.up) && speed < max) speed += 0.8; //按向上鍵速度增加
if (Key.isDown(key.down) && speed > -max) speed -= 0.4; //因為退車速度會比較慢

_x += posX * speed; //設定車子的x和y, 當然重要的步驟是以上的posX和posY, 還有下方的弧度計算
_y += posY * speed;
_rotation = degree;

if ( speed > 0 ) speed -= 0.25;
if ( speed < 0 ) speed += 0.25;

angle = (degree*(Math.PI/180));
}
}