Problem with formmail

I am using the code below to send an e-mail form.
It sends the e-mail, but it also opens a new window that
says “Thank You For Filling Out This Form”.
How can I get rid of this message, and the new window.
I am using the Matt’s

You can view the site at

var address:String = “”;
var url:URLRequest;
var variables:URLVariables = new URLVariables();
variables.subject = “Information Send From Palisade Academy Web Site”
variables.recipient = "[email protected]"

submit_btn.addEventListener(MouseEvent.CLICK, sendform);

function sendform(event:MouseEvent):void
{ = name_txt.text; = email_txt.text;
variables.address = adress_txt.text; = phone_txt.text;

url = new URLRequest(address);
url.method = URLRequestMethod.GET; = variables;