<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
<mx:Script>
<![CDATA[
import flash.net.navigateToURL;
private function goToURL() : void
{
navigateToURL( new URLRequest( newUrl.text ),
target.selectedItem as String );
}

]]>
</mx:Script>
<mx:TextInput id="newUrl" top="10" left="10" right="10" text="http://www.oreilly.com/" />
<mx:ComboBox id="target" top="40" left="10" dataProvider="{ [ '_blank', '_self' ] }" />
<mx:Button label="Go" left="10" top="70" click="goToURL()" />
</mx:Application>