flask show while calculating

[ndc85430]

You don't send data to HTML files. If the server is doing these calculations, the results need to be sent to the client (i.e. the browser). The browser can make an AJAX request to ask for that data (so will need to ask repeatedly for updates), or you can have the server push the data to the client with WebSockets or socket.io for example. As I said earlier, HTTP is request/response, so you'll have to poll the server unless you want to look at WebSockets/socket.io.