save data before close browser

Dear Friends,

iam loading my swf file in aspx file on the browser, when i click a button i will pass 2 variables to database and close or unload. If the user close the browser withtout click on that button i want to post that values and save in the dtabase. how can i do that pls explain me.

find below the code i used to store data when i click a button.

var variables:URLVariables = new URLVariables();

var varSend:URLRequest = new URLRequest("lmsHome.aspx");

var varLoader:URLLoader = new URLLoader;

varSend.method = URLRequestMethod.POST;

varSend.data = variables;

frdbut.addEventListener(MouseEvent.CLICK,sendMessage);

function sendMessage(event:MouseEvent):void {

    variables.elecode = lescode;

    variables.eleduration = "2:0"

    varLoader.load(varSend);

}

Thanks in advance,

Syed Abdul Rahim