<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" verticalAlign="middle" backgroundColor="white" viewSourceURL="srcview/index.html">

    <mx:Script>
        <![CDATA[
            private function intToHex(color:int = 0):String {
                var mask:String = "000000";
                var str:String = mask + color.toString(16).toUpperCase();
                return "#" + str.substr(str.length - 6);
            }
        ]]>
    </mx:Script>

    <mx:Box id="box" width="200" height="100" backgroundColor="{slider.value}" />

    <mx:HSlider width="{box.width}" id="slider" minimum="0x000000" maximum="0xFFFFFF" liveDragging="true" dataTipFormatFunction="intToHex" />

</mx:Application>