SetInterval used inside a Function not working

programming flash
1

If I place some working setInterval code within a function and then call the function, it fails:


function RevealLinks():Void {
    menu_mc._visible = true;
    // Begin with Menu Links hidden
    for (var i = 0; i < 12; i++) {
        _root.menu_mc["item" + i + "_mc"]._visible = false;
    }
    clearInterval(thisID);
    var thisID:Number;
    var count:Number = 0;
    var maxCount:Number = 11;
    var duration:Number = 100;
    function executeCallback():Void {
        _root.menu_mc["item" + count + "_mc"]._visible = true;
        if (count >= maxCount) {
            clearInterval(thisID);
        }
        count++;
    }
    thisID = setInterval(this, "executeCallback", duration);
}
RevealLinks();

Can someone remind me why this sort of thing doesn’t work?