javascript - How to negate bool inside function in JS?

I'm writing some script now and I have a problem when trying to
negate boolean inside a function. I mean
this:

var test =
            true;

function changeThisBoolPlease(asd){

            asd=!asd;
}

alert(test);


            changeThisBoolPlease(test);
alert(test);

alerts
true, then true.

Any ideas? Isn't JS reference
perfect?

EDIT:

Ok,
this was only a part of my
function:

function przesun(kolor,
            figury, castlings, x1, y1, x2, y2, strona) {
 kolor =
            nowaPozycjaKolor(kolor,x1, y1, x2, y2);
 figury = nowaPozycjaFigur(figury,x1,
            y1, x2, y2);
 strona =
            !strona;
}

Actually
I cannot return this value. How to?

class="post-text" itemprop="text">

class="normal">Answer

Objects
are not passed by reference but by value which is a reference (copy of
reference)...

In your example you're not even
passing an object but a primitive value type.

If
you want a reference, then you need to wrap it in object element
like:

var test = { val: true
            };

function changeThisBoolPlease(asd){


            asd.val=!asd.val;
}

alert(test.val);
changeThisBoolPlease(test);
alert(test.val);