import flash.display.Sprite;
import flash.events.Event;

var s1:Sprite = new Sprite()
addChild(s1)
stage.addEventListener(Event.ENTER_FRAME,px)
function px(evt:Event):void{
 draw()
 }
  function draw():void{
 s1.graphics.clear() //理解：每次繪制都刪除已經(jīng)繪制的線模擬電流的隨機(jī)變動
 s1.graphics.lineStyle(1,0xff0000)
 s1.graphics.moveTo(0,100)
   for(var i:int=0;i<500;i=i+3 ){
    var xr:int=i
    var yr:int=90+20*Math.random()
    s1.graphics.lineTo(xr,yr)
    }
  }