监听localStorage.setItem方法

dispatchEventStroage (){
      const signSetItem = localStorage.setItem
      localStorage.setItem = function (key, val) {
        let setEvent = new Event('setItemEvent')
        setEvent.key = key
        setEvent.newValue = val
        window.dispatchEvent(setEvent)
        signSetItem.apply(this, arguments)
      }
    }

window.addEventListener('setItemEvent', function (e) {
        if(e.key && e.newValue && e.key == "xxx"){
          alert("进入");
        }
      })