package {
import flash.net.URLLoader
import flash.net.URLRequest
import flash.xml.XML;
import flash.display.*;
import flash.events.*;
import flash.text.*;
import flash.geom.*;

/*
requires xml document named "test.xml" that looks like:
<?xml version='1.0' encoding='UTF-8' standalone='yes'?>
<!-- rollover dynamic text in flash 9 -->
<document>
<string linkText = "these words"><![CDATA[Flash 9 is freakin' hot! Just roll over <b><u>these words</u></b> to see another reason why...]]></string>
</document>

*/
public class DynTextLink extends Sprite {

private var _fmt:TextFormat;
private var _xml:XML;
private var _tf:TextField;
private var _s:String;
private var _linkText:String;
private var _output:TextField;
private var _loader:URLLoader;
public function DynTextLink() {
_loader = new URLLoader();
_fmt = new TextFormat("Tahoma", 11, 0x000000);

loadXML();
}

private function loadXML():void {
_loader.addEventListener(Event.COMPLETE, onXMLloaded);
_loader.load(new URLRequest("test.xml"));
}
private function onXMLloaded(e:Event):void {
_xml = new XML(_loader.data);
_xml.ignoreWhitespace = true;
_s = _xml.string[0].toString();
_linkText = _xml.string[0][email protected]();
createTextFields();
}
private function createTextFields():void {
_tf = new TextField();
_tf.width = 500;
_tf.height = 100;
_tf.selectable = false;
_tf.x = 50;
_tf.y = 50;
_tf.htmlText = _s;
_tf.setTextFormat(_fmt);

_output = new TextField();
_output.width = 500;
_output.height = 100;
_output.selectable = false;
_output.x = 50;
_output.y = 150;

addChild(_tf);
addChild(_output);

createButton();
}
private function createButton() {
var index:Number = _tf.text.indexOf(_linkText);
var r:Rectangle = _tf.getCharBoundaries(index);
var r2:Rectangle = _tf.getCharBoundaries(index + _linkText.length);
var textButton:Sprite = drawSprite(r2.x - r.x, r.height);
textButton.x = r.x + _tf.x;
textButton.y = r.y + _tf.y;
textButton.addEventListener(MouseEvent.ROLL_OVER, onTextButtonRollOver);
textButton.buttonMode = true;
}
private function onTextButtonRollOver(e:MouseEvent):void {
_output.text = "You just triggered a roll over event with dynamic text!";
_output.setTextFormat(_fmt);
}
function drawSprite(w:Number, h:Number):Sprite {
var s:Sprite = new Sprite();
s.graphics.beginFill(0x000000, 0);
s.graphics.drawRect(0, 0, w, h);
addChild(s);
return s;
}
}
}

http://www.kirupa.com/forum/archive/index.php/t-236621.html

overlay button on dynamic text

ActionScript 3