If statement on global variable doesn't execute function gotoAndStop();

Question

I'm making a simple concept game, in which I've made buttons which are targets, when the user clicks said targets, it executes this code:

on (release){
    _global.targetCount++;
    Target1._visible=false;


    if(_global.targetCount==3){
        gotoAndStop(4);
    }

}

the global variable was declared on the frame like this:

_global.targetCount = 0;

and the buttons do disappear when I click on them like they should, but as soon as I click the final 3rd one and it disappears, it doesn't successfully check that the if(_global.targetCount==3) and proceed to the 4th frame.

I've tried declaring the variable differently like so:

var targetCount:Number = 0;

also tried doing it like this but on using the check code button it said my syntax was wrong:

var _global.targetCount:Number = 0;

and calling every instance as just targetCount, but that didn't fix it either,

I've searched and tinkered with the code, but I can't find clear examples on global variables, the little I've used here I found by reading this:

https://www.kirupa.com/developer/actionscript/tricks/global.htm

So I was wondering if anyone here could help me by letting me know the many mistakes I've done, and how to improve them.

All help is gladly appreciated!