Javascript Box JWT authentication Issues

Hi Friends,

I have developed some javascript code to access to box with JWT authentication.

Trying to get JWT token using javascript in stage environment and getting below error, We are trying to hit the https://api.box.com/oauth2/token from javascript, with grant_type : "urn:ietf:params:oauth:grant-type:jwt-bearer".

Error messages from the scripts:

{"error":"invalid_request","error_description":"Invalid grant_type parameter or parameter missing"}

My first script is like bellow:

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My Second script is like bellow:

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Please someone guide us about what was went wrong in script and why did I get invaild param message from box server.

Thanks.