javascript - How to tell if new location is forcing file download?

Question

I am redirecting user using window.location.href to a page that forces a file download using the following headers:

Content-Description: File Transfer
Content-Disposition: attachment; filename="foo"

As a result, user is not taken to the page, though asked if he wishes to proceed downloading the file.

How do I tell when the response from the server is received?

The user flow that I am trying to achieve:

1. Display loader.
2. "redirect" the user (with window.location.href).
3. Hide loader when response is received.

Answer 1

• 从您的客户端代码中，还将生成的 ID 传递给服务器，要求它为您设置一个 cookie 为该值。
• 您的服务器端代码应将 cookie 与下载的文件（在 HTTP 标头中）一起传回。
• 然后，您可以在重定向后轮询 javascript 中的 cookie，以查看服务器何时响应成功连接。