<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/08/09/determining-which-serverdomain-a-swf-is-hosted-on/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" applicationComplete="init()">

    <mx:Script>
        <![CDATA[
            import mx.utils.URLUtil;

            private function init():void {
                lbl.text = "url=" + URLUtil.getServerName(Application.application.loaderInfo.url);
            }
        ]]>
    </mx:Script>

    <mx:Label id="lbl" text="" />

</mx:Application>