Ajax / php - How to return failure

Question

jquery allows for success failure and error responses. How can i return a failure or error manually along with a string that describes the failuer or error?

Answer 1

It has become somewhat of a convention to utilize a simple JSON envelope to report failures that occurred on the server side (that are not HTTP errors).

The flickr api provides a typical packaging example:

look at the bottom of this page for success and failure examples

So in the case of an Ajax call to the flickr API, in your success callback you would check the returning data for success/failure

$.ajax({   
  //...   
  success:   function(data) {
    if(data.stat == 'fail') {
       //data.code + data.message contain details that could be used here
    }
    else {
      //do success stuff here
    }
  }
});