<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/08/26/programmatically-scrolling-a-textarea-control-in-flex/ -->
<mx:Application name="TextArea_verticalScrollPosition_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        creationComplete="init();">

    <mx:Script>
        <![CDATA[
            import mx.events.SliderEvent;

            private function init():void {
                callLater(setMaxVScrollPos);
            }

            private function setMaxVScrollPos():void {
                slider.maximum = textArea.maxVerticalScrollPosition;
            }

            private function slider_change(evt:SliderEvent):void {
                textArea.verticalScrollPosition = evt.value;
            }
        ]]>
    </mx:Script>

    <mx:String id="lorem" source="lorem.html" />

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="verticalScrollPosition:">
                <mx:HSlider id="slider"
                        minimum="0"
                        snapInterval="1"
                        liveDragging="true"
                        change="slider_change(event);" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:TextArea id="textArea"
            htmlText="{lorem}"
            verticalScrollPolicy="on"
            width="100%"
            height="100%"
            resize="init();" />

</mx:Application>