[RDA]

Не знаю может есть вариант и попроще......

this.createTextField("temp", 1, 10, 10, 200, 50);
this["temp"].wordWrap = this["temp"].multiline = this["temp"].border = true;
this["temp"].type = "Input";
this["temp"].variable = "txt";
///
this["temp"].onSetFocus = function() {
	Selection.setFocus("this.txt");
	this._parent.onEnterFrame = function() {
		this.begin = Selection.getBeginIndex();
		this.end = Selection.getEndIndex();
	};
};
///
this["temp"].onKillFocus = function() {
	delete this._parent.onEnterFrame;
};
///
this.createEmptyMovieClip("button", 10);
this["button"].beginFill(0xcccccc, 100);
this["button"].moveTo(150, 70);
this["button"].lineTo(210, 70);
this["button"].lineTo(210, 90);
this["button"].lineTo(150, 90);
this["button"].lineTo(150, 70);
this["button"].endFill;
///
this["button"].onRelease = function() {
	trace(this._parent["txt"].substring(this._parent["begin"], this._parent["end"]));
};
///