Getting error though used Base64 Library to extract the details from JWT token?

I went through this question:
http://answers.neotys.com/questions/2587608-javascript-decode-jwt-token

Im trying to decode jwt token and have to use the details available in the Payload(second header).
I'm hitting jwt.io and sending my token in POST request as Text but its not working and no response
Could you please share more details ?