How can I send JSON data to ASP Server using AJAX?

I have a website using ASP.NET that needs to retrieve some data from CloudKit. I am using CloudKit JS and I am retrieving a record from CloudKit and sending the data to the server from my JavaScript using C#. I am able to turn the JSON object of the retrieved record into a string using JSON.stringify(record);, but I am unable to send it to the server using AJAX. Here is my code for sending the data using AJAX: