Cc.spawn, cc.instantiate, cc.destroy question

Hi,

I have a bullet node which I cc.instantiate through the **player node ** by calling the bullet node through:

var bullet = cc.instantiate(this.footballbullet);
// Place Bullet on Screen
this.footballbullet.setPositionX(500),
this.footballbullet.setPositionY(150),
this.node.addChild(bullet)},

When I press the Space Bar, I would like the bullet to shoot accross the screen, then I have in the Bullet Node, this:

update: function (dt) {
//If X < = -615 then Destroy Object
if (this.node.x<=-615) {
// Destroy Node (Object)
this.node.destroy();}

So my question is should I be using destroy? Is there any difference between spawn, instantiate ? The thing is that I see the bullet racing across the screen, but if I Press the Space Bar it gets instantiated it in but it never finishes moving across the screen. What I’m looking for is a simple demonstration or tutorial, that will teach me how to constantly press the space bar continue shooting the bullet…Should I use a Prefab instead of node for the bullet? Would appreciate any feedback…Thanks for reading and God Bless…

Sincerely,

Sunday