AS3 Variable is changing back to initial state

programming flash
1

I set a variable

var currentPage:String = “b1”;

When I click a button, the click should change the variable currentPage to the event.currentTarget.name and it does

function btnClick(event:MouseEvent):void
{
currentPage = event.currentTarget.name;
}

after the click, I do a rollover and trace currentPage, and currentPage is now set back to it’s initial state, “b1”

What is going on here?
What is changing it back, or this correct behavior?
I even tried with an array using currentPage[0]


var cPage:Array = new Array("");
var btnArray = [b1,b2,b3,b4,b5,b6,b7];
for each (var navBtn in btnArray)
{
    navBtn.addEventListener(MouseEvent.CLICK, navClick);
    navBtn.addEventListener(MouseEvent.ROLL_OVER, navOver);
    navBtn.addEventListener(MouseEvent.ROLL_OUT, navOut);    
}

function navClick(event:MouseEvent):void
{
    trace("Current target is "+event.currentTarget.name);
        
    if (cPage[0] == event.currentTarget.name)
    {
        
    }
    else
    {

        Tweener.addTween(this[String(cPage[0]+"t")],{_color:0xFFFFFF,time:1,transition:"easeOutBack"});
        Tweener.addTween(this[String(cPage[0]+"p")],{x:62, y:-480,time:1,transition:"easeOutBack"});
        Tweener.addTween(this[String(event.currentTarget.name+"p")],{x:62, y:217,time:1,delay:1,transition:"easeOutBack"});
        cPage[0] = event.currentTarget.name;
        trace("Now cPage is-"+cPage[0]);
        
    }
}

function navOver(event:MouseEvent):void
{
    trace("cPage is "+cPage[0])
    Tweener.addTween(this[String(event.target.name+"t")],{_color:0xFAD183,time:.5,transition:"easeOutBack"});
}