IE11以下不支援localStorage，若瀏覽器不支援，使用cookie儲存

var util = {
  // 獲取 localStorage
  getItem: function (item) {
    var value;
    if (this.hasLocalSotrage()) {
      try {
        value = localStorage.getItem(item);
      } catch (error) {
        console.error('localStorage.getItem報錯， ', error.message)
      } finally
 
 {
        return value;
      }
    } else {
      return this.getCookie(item);
    }
  },
  // 設定 localStorage
  setItem: function (key, value, day) {
    if (this.hasLocalSotrage()) {
      try {
        // safari 無痕模式下，直接使用localStorag.setItem 會報錯
        localStorage.setItem(key, value);
      } catch
 
 (error) {
        console.error('localStorage.setItem報錯， ', error.message)
      }
    } else {
      this.setCookie(key, value, day);
    }
  },
  // 判斷瀏覽器是否支援 hasLocalSotrage
  hasLocalSotrage: function () {
    return window.Storage && window.localStorage && window.localStorage instanceof
 
 Storage
  },
  //設定cookie
  setCookie: function (key, value, day) {
    var t = day || 30;
    var d = new Date();
    d.setTime(d.getTime() + (t * 24 * 60 * 60 * 1000));
    var expires = "expires=" + d.toUTCString();
    document.cookie = key + "=" + value + "; " + expires;
  },
  //獲取cookie
  getCookie: function (name) {
    var arr, reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");
    if (arr = document.cookie.match(reg)) {
      return arr[2];
    }
    else {
      return null;
    }
  }
}