根据

According to MDN you can't do cross domain access to an indexedDB (for security reason, you don't want that another website modify your client database):

IndexedDB遵循同源策略.因此，尽管您可以访问域中存储的数据，但不能跨不同域访问数据.

IndexedDB follows a same-origin policy. So while you can access stored data within a domain, you cannot access data across different domains.

另请参阅:

• 从浏览器存储中跨域读取数据
• 是Chrome扩展程序能否访问由特定域创建的IndexedDB数据库?