let timer = setInterval( handler: () => {

              this.time --

              this.btnText='$(this.time)s后重新发送'

              this.disabled = true

              if (this.time == 0){

                this.disabled = false

                this.btnText = '重新发送'

                this.time = this.countDown

                clearInterval ( timer)

              }

            }, timeout: 1000)