[]HTMLDivElement如何设置文本区域内可以上下拖动的效果

package 

{

	import laya.display.Sprite;

	import laya.events.Event;

	import laya.html.dom.HTMLDivElement;

	import laya.maths.Rectangle;

	import laya.webgl.WebGL;



	public class HelloLaya 

	{

		private var html:HTMLDivElement;

		public function HelloLaya() 

		{

			Laya.init(600, 600,WebGL);

			Laya.stage.bgColor="#eeffcc";

			

			var sp:Sprite=new Sprite();

			sp.graphics.drawRect(50,50,300,300,null,"#0000FF",2);

			Laya.stage.addChild(sp);

			

			html=new HTMLDivElement();

			html.innerHTML="<span>哈哈哈哈哈</span>";

			Laya.stage.addChild(html);

			html.on(Event.MOUSE_DOWN,this,onHtmlDown);

		}

		

		private function onHtmlDown():void

		{

			html.startDrag(new Rectangle(50,50,300,300),false,10);	

		}

	}

}