How to change a as2 quit button .as file

[Lilly4u]

Hello, I am working in someone else's code that no longer works at our company, I am not a coder, and have been doing research to change his coding so that I can close the swf file loaded into a browser window. Can anyone help? I am very lost! thank you!!

This is what is currently in the .as file:

1st appearance of btn in code:

function startGame():Void
{
    clearContainer();
    createContent(0, 0, 100, 10, "bg_main");                //create main bg at layer 10
    createContent(655, 54, 100, 20, "carl2_"+area);            //create carl at layer 20
    createMask();                                            //create carl mask at layer 30
    createContent(20, 10, 100, 40, "title2_"+area);            //create title at layer 40
    createHintText(termArr[termIndex]);                        //create hint text at layer 50
    createContent(27, 380, 100, 60, "pc");                    //create pc at layer 60
    createKeyborad();                                        //create key board at layer 70
    createContent(818, 250, 100, 80, "feedback");            //create feedback at layer 80
    createButtonNext();
    createButtonSolve();
    createDisplay(termArr[termIndex]);
    createTryText(termArr[termIndex].times);
    createButtonQuit();
}
 
function createButtonQuit():Void 
{
    createContent(917, 40, 100, 130, "btn_quit");
 
    container.btn_quit.onRelease = function(){ 
        playSound("click");
        unloadMovieNum(loadLevel);
    }
}
 
//functions for creating ending page
function endingPage():Void 
{
    clearContainer();
    createContent(0, 0, 100, 10, "bg_main");                //create main bg at layer 10
    createContent(90, 100, 100, 20, "text_end");            //create ending text at layer 20
    createContent(20, 10, 100, 40, "title2_"+area);            //create title at layer 40
    createContent(480, 80, 100, 60, "carl1_"+area);            //create intro Carl at layer 60
    createButtonAgain();    //depth 70
    createButtonQuit();
}

Thank you for any help you can offer!! I really appreciate it!