Fitbit Chrome Extension using only client side code

Question

I'm building a Chrome Extension application that will only allow a user to visit certain websites if the user has completed 10k steps. I am having trouble with the Fitbit API (https://wiki.fitbit.com/display/API/Fitbit+API). I'd like all the code to be in the client but I'm having trouble figuring out how to authenticate and make requests to Fitbit from an extension. I already added permissions to my manifest.json so that I won't have to worry about CORS. Anyone have experience with this? I can only find information on how to use a server to authenticate with the Fitbit API.

Here is my attempt at the first call to Fitbit to begin the OAuth:

    $.ajax({
        'url' : 'api.fitbit.com',
        'type' : 'POST',
        'data' : {
          'oauth_signature_method' : "HMAC-SHA1",
          'oauth_timestamp' : Date.now(),
          'oauth_nonce' : "161822064",
          'oauth_callback' : "http%3A%2F%2Fexample.fitbit.com%2Fapp%2FcompleteAuthorization",
          'oauth_signature' : "Omf%2Bls2gn%2BDlghq245LRIyfMdd8%3D",
          'oauth_version' : "1.0",
          'oauth_consumer_key' : "fitbit-example-client-application"
        },
        'success' : function(data) {
          console.log(data);
        }
      });