btn.addEventListener(MouseEvent.CLICK,onClick);

function onClick(evt:MouseEvent){

    navigateToURL(new URLRequest("http://www.163.com"));

}

调用js方法打开新窗口链接（预防ie7阻止弹窗）

import flash.external.ExternalInterface;
function openWindow(){
    var url:String = "http://www.blueidea.com";
    var windowName:String = "mywindow";
    var windowOptions:String = "width:800,height:600";
    ExternalInterface.call("window.open",url,windowName,windowOptions);
}