Question

MovieClip.prototype.sMove = function(speed, tarY)

MovieClip.prototype.sMove = function(speed, tarY) {
speedY = speed*(tarY-this._y);
this._y += speedY;
这是怎么控制速度的，能让他匀速吗

Answer 1

改成
MovieClip.prototype.sMove = function(speed, tarY)
{
if(this.oy == undefined)
this.oy = this._y;
speedY = speed*(tarY-this.oy);
this._y += speedY;
}