限制动态对象的可能定位？

Question

I have a function to generate enemy ships (Movie clip) and have them 'fly' across the stage at different heights. The problem I have is I want to limit this so that there is a 600 x 75px space at the top of the stage that the enemy ships do not fly across so that I can display the score and timer without the ships flying across them (So they can be easily seen). My stage is 600 x 350px. I am just wondering if this is the best way to do this? The code for the function that generates the ships is below:

function EnemyShipSmall()
    {
        this.x = 800;
        this.y = Math.random() * 300;
        speed = Math.random()*5 + 5;
        addEventListener("enterFrame", enterFrame);
    }

Thanks.

Answer 1

Try this :

function EnemyShipSmall()
    {
        this.x = 800;
        this.y = Math.random() * 275 + 75;
        speed = Math.random()*5 + 5;
        addEventListener("enterFrame", enterFrame);
    }