import flash.display.Shape;
import flash.events.MouseEvent;
import flash.geom.Point;
var line:Shape;
var point:Point;
stage.addEventListener(MouseEvent.MOUSE_DOWN,drawBegin);
stage.addEventListener(MouseEvent.MOUSE_UP,drawEnd);
function drawBegin(e:MouseEvent):void {
line= new Shape();
addChild(line);
point = new Point(mouseX,mouseY);
stage.addEventListener(MouseEvent.MOUSE_MOVE,drawing);
}
function drawing(e:MouseEvent):void {
line.graphics.clear();
line.graphics.moveTo(point.x,point.y);
line.graphics.lineStyle(2,0);
line.graphics.lineTo(mouseX,mouseY);
e.updateAfterEvent();
}
function drawEnd(e:MouseEvent):void {
stage.removeEventListener(MouseEvent.MOUSE_MOVE,drawing);
}