Set interval problem

Question

I'm trying to generate an instance of a logo every two
seconds and have them remain persistent. This code creates a new
instance every two seconds but the earlier versions are deleted.
Any ideas of how to do this would be helpful.
function createLogo():Void {
var counter:Number;
counter++
var copy:MovieClip = attachMovie("logo", "newLogo" +
counter, counter);
["copy" + counter]_x = Math.floor(Math.random() * (0-650));
["copy" + counter]_y = -60;
var myInterval:Number = setInterval(createLogo, 2000);

Answer 1

Trace your counter value. I think you will see that it isn't
what you think!
There are probably several things wrong with this. First you
can't increment a value that doesn't already have a value. It used
to be that a variable without a value was assumed to be zero, but
now-a-days...
The next thing is that you really need to have the counter
variable be outside the function. You want it to persist from
function call to function call. But by having it declared as var
inside the function it is local to the function. So as soon as
createLogo is done counter goes away and isn't kept for the next
round.
Finally, this isn't specific to what you have asked, but it
is just advice. Generally there can be lots of counters in your
code. So it is just fine to name it counter when it is local to a
function. But once you move it out of a function (where it might
interfere with other counter(s). You might want to rename it to
something more identifiable. Like logoCount or some such.