element多个表单，对单个表单进行验证

this.$refs[formName].validateField('mobile', valid => {
                 console.log(valid)
                    if(!valid) {
                      if (!this.timer) {
                        this.count = TIME_COUNT
                        this.show = false
                        this.timer = setInterval(() => {
                          if (this.count > 0 && this.count <= TIME_COUNT) {
                            this.count--
                          } else {
                            this.show = true
                            clearInterval(this.timer)
                            this.timer = null
                          }
                        }, 1000)
                      }    
                    }
               })