The Sencha ExtJS definition of success

One of the most important things I’ve read in the book, Mastering ExtJS, is this: “For ExtJS, success is when the server returns a response, and failure is when the server returns an HTTP error status.” So if the server returns some form of ‘success’ -- regardless of what its JSON looks like -- ExtJS will think of the transaction as a success, and you should handle that in an ExtJS success function. If the server returns an HTTP error status, such as a 200 status code, you should handle that in an ExtJS failure function. See pp. 60+ of the book for more details.