1: in mounted () {
this.timer = setInterval(() => {
    this.rechargeInfo();
}, 3000);} create a timer. 
 2: 
 beforeDestroy () {
this.timer = null;
clearInterval(this.timer);}, 
 destroyed () {
this.timer = null;
clearInterval(this.timer);} to clear 
. 
 in theory, the timer is cleared when the component is destroyed. , 
 but: the timer is still running when you jump to another page. 
 question. 
