Testings.mxml

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication
    xmlns:fx="http://ns.adobe.com/mxml/2009" 
    xmlns:s="library://ns.adobe.com/flex/spark" 
    xmlns:mx="library://ns.adobe.com/flex/halo"
    applicationComplete="appComplete()"
    width="640"
    height="480">
    <fx:Script>
        <![CDATA[
            private function appComplete():void
            {
                trace("onAppComplete()");
                var loader:HTMLLoader = new HTMLLoader();
            }
        ]]>
    </fx:Script>
</s:WindowedApplication>