代码如下：
//定义速度变量
var speed:Number = 0;
var car_speed:Number = 0;
//增加键盘侦听器
Key.addListener(_root.road_mc);
road_mc.onEnterFrame = function() {
//键盘UP键按下
if (Key.isDown(38)) {
if (road_mc._y<-80) {
road_mc._y += speed;
speed_func();
car_speed_func();
//trace(speed);
car_mc._y>=166 car_mc._y -= car_speed : 正常;
} else {
road_mc._y = -437;
}
//键盘UP键放开
} else if (road_mc._y<-80) {
if (speed>=0.25) {
speed -= 0.25;
road_mc._y += speed;
//trace(speed)
//trace(road_mc._y)
}
} else {
road_mc._y = -437;
}
//键盘LEFT键
if (Key.isDown(37)) {
if (car_mc._x>76) {
speed<3 car_speed=speed : car_speed=3;
car_mc._x -= car_speed;
}
}
//键盘RIGHT键
if (Key.isDown(39)) {
if (car_mc._x<378) {
speed<3 car_speed=speed : car_speed=3;
car_mc._x += car_speed;
//trace(car_speed);
}
}
//键盘DOWN键
if (Key.isDown(40)) {
if (speed>0) {
car_mc<331 car_mc._y += 5 : 正常;
speed -= 2;
} else {
speed = 0;
}
}
//加速"shift"键
if (Key.isDown(Key.SHIFT) && !this["press"]) {
this["press"] = true;
car_mc.play();
speed<150 speed += 50 : 正常;
var This = this;
this["interval"] = setTimeout(function () {
car_mc.gotoAndStop(1), This["press"]=false;
}, 5000);
//设置延时5000毫秒
}
};
//声明函数,按当前速度渐加
function speed_func() {
if (speed<10) {
speed += 0.25;
} else if (speed<20) {
speed += 0.5;
} else if (speed<30) {
speed += 1;
} else if (speed<50) {
speed += 1.5;
} else if (speed<80) {
speed += 3;
} else if (speed<0) {
speed = 0;
}
}
