begin(){
    var that=this;
    if(that.data.animationData==''){
      var animation = wx.createAnimation({
        duration: 300,
        timingFunction: 'ease-out',
      })

      this.animation = animation

      animation.translate(0, -650).step()

      this.setData({
        animationData: animation.export()
      })
    }
    else{
      var animation = wx.createAnimation({
        duration: 500,
        timingFunction: 'ease-out',
      })

      this.animation = animation

      animation.translate(0, 650).step()

      this.setData({
        animationData: animation.export()
      })
        that.setData({
          animationData: ''
        })
    }
    
  }