使用CodeIgniter中的JSON数据自动填充输入框

Sorry I am racking my brain and I have not worked with this in a long time. I have a form that you put a phone number in and on change submits an AJAX call to the database which post's the data and query's the database. Then sends a response back to the page which I am seeing the response values via Firebug in Firefox, but for the life of me I can not figure out how to get the data to update the text box fields with the information. Any help would be great. Also this is using CodeIgniter's framework and the data is being Sorry I am racking my brain and I have not work