Flash AS2 (CS4) - setInterval causing for loop to not work

I have some simple code:

    function testing(){
       for (a=1; a<=4; a++) {
           this["btn"+a].enabled = true;
       }
    }

If i run this function from anywhere it works fine. If i run this function from myTimer = setInteval(testing, 3000); it will not work. If i add other random code into the function it (the newly added code only) will work. So i have narrowed it down to something about this["btn"+a].enabled = true; specifically that is causing it to not run.

I really hope this makes sense, appologies, it's 3am :(开发者_如何学编程.

Any ideas?

---

What you say makes sense. When you call that function normally, "this" is your object. When you run it by using setInterval, you lose the reference to your "this."

- Edited based on comments to help others -

Here are 3 ways to solve this problem:

This way involves passing in "this" to your function:

var that = this;
setInterval(function() {testing(that)}, 1000);

function testing(obj) {
    for (a = 1; a <= 4; a++) {
        obj["btn" + a].enabled = true;
    }
}

This way involves passing in "this" to setInterval:

setInterval(this, "testing", 1000);

function testing() {
    for (a = 1; a <= 4; a++) {
        this["btn" + a].enabled = true;
    }
}

The third way involves the Delagate class:

import mx.utils.Delegate;

setInterval(Delegate.create(this, testing), 1000);

function testing() {
    for (a = 1; a <= 4; a++) {
        this["btn" + a].enabled = true;
    }
}