Help with on release gotoAndPlay

Question

Hello -
I am working on a Flash project that was using AS2.  I now need to update it to AS3.  This specific item is for a button that will Close when clicked on and then start playing at frame 400.  The button has an instance name of Close.
Can anyone teach or tell me how to convert the following code to AS3?
on (release) {
    gotoAndPlay(400);
Thank you!!!

Answer 1

Thank you again for helping me learn this.  I am taking an AS3 class next month.
I keep getting the following error now.  I updated the button instance name to lowercase and also gave the movie clip that the button resides in an instance name of disclosuremc.  The movie ends on frame 450 but I want the button to start at frame 400 on the main timeline (scene 1) when clicked on.  All of the other code works fine, it's just the last few lines that deal with the button named closebtn.
TypeError: Error #1009: Cannot access a property or method of a null object reference.
    at Sample_fla::MainTimeline/frame450()
Here is my AS3
stop();
Link_2.addEventListener(MouseEvent.MOUSE_UP, function(event: MouseEvent): void {
var sURL: String;
if ((sURL = root.loaderInfo.parameters.clickTag2)) {
navigateToURL(new URLRequest(sURL), "_blank");
Link_3.addEventListener(MouseEvent.MOUSE_UP, function(event: MouseEvent): void {
var sURL: String;
if ((sURL = root.loaderInfo.parameters.clickTag3)) {
navigateToURL(new URLRequest(sURL), "_blank");
Link_4.addEventListener(MouseEvent.MOUSE_UP, function(event: MouseEvent): void {
var sURL: String;
if ((sURL = root.loaderInfo.parameters.clickTag4)) {
navigateToURL(new URLRequest(sURL), "_blank");
Link_5.addEventListener(MouseEvent.MOUSE_UP, function(event: MouseEvent): void {
var sURL: String;
if ((sURL = root.loaderInfo.parameters.clickTag5)) {
navigateToURL(new URLRequest(sURL), "_blank");
legal.addEventListener(MouseEvent.CLICK, clickFunction);
function clickFunction(evt:MouseEvent):void {
gotoAndStop(341);
replay.addEventListener(MouseEvent.CLICK, onClick);
function onClick(event:MouseEvent):void
     gotoAndPlay(1);
disclosuremc.closebtn.addEventListener(MouseEvent.CLICK, onClick2);
function onClick2(event:MouseEvent):void
     gotoAndPlay(400);