localStorage四種方法:
localStorage.getItem(key):獲取指定key本地儲存的值
localStorage.setItem(key,value):將value儲存到key欄位
localStorage.removeItem(key):刪除指定key本地儲存的值
localStorage.length是localStorage的專案數
localStorage.getItem(key):獲取指定key本地儲存的值
localStorage.setItem(key,value):將value儲存到key欄位
localStorage.removeItem(key):刪除指定key本地儲存的值
localStorage.length是localStorage的專案數