Button setting the variable

programming flash
1

Here’s what I need:
In the first frame I’ve created two buttons, one is supposed to set the variable to true, and the other sets the variable to false. Later on the timeline I’ve set up a movieclip - if the variable is true, the alpha = 100, but if the variable is false then alpha = 0. (this is to turn the subtitles on/off). Could someone help me make this work? I don’t know what I’m doing wrong…

**ON Button
**on(release){
var subsOn = true;
}

**OFF Button
**on(release){
var subsOn = false;
}

Movieclip:
onClipEvent(enterFrame) function() {
if(subsOn == true){
setProperty(subs, _alpha, 100);
}
if(subsOn == false){
setProperty(subs, _alpha, 0);
}
}