How can I make the user upload a JSON file?

[v9um]

No need to java script.
Use the compress extension
and the base 64 extension.
This topic might help:

Decompressing A Compressed String Isnt Working

I have a game with a level editor feature that allows users to save their tracks by copying a code. However, I encountered an issue when I created a large track. The code length exceeded the clipboard limit, preventing me from copying the entire code. To solve this issue, I used the Compress extension to minimize the code length. While the compression worked successfully, I encountered a new problem when attempting to load the compressed code back into the game. The game would produce an error …