JQuery error option in $.ajax utility

Question

The documentation indicates that the error: option function will make available: XHR instance, a status message string (in this case always error) and an optional exception object returned from the XHR instance (Book: JQuery in Action)

Using the following (in the $.ajax call) I was able to determine I had a "parsererror" and a "timeout" (since I added the timeout: option) error

error: function(request, error){}

What are other things you evaluate in the error option? do you include the optional exception object?

EDIT: one of the answers indicates all the return errors...learning more about what is of value (for debugging) in the XHR instance and exception object would be helpful

This is a complete $.ajax call:

$.ajax({
 type: "post",
 url: "http://myServer/cgi-bin/broker" ,
 dataType: "text",
 data: {
 '_service' : 'myService',
 '_program' : 'myProgram',
 'start' : start,
 'end' : end
 },
 beforeSend: function() {
  $("#loading").removeClass("hide");
 },
 timeout: 5000,
 error: function(request,error) {
  $("#loading").addClass("hide");
  if (error == "timeout") {
   $("#error").append("The request timed out, please resubmit");
  }
  else {
   $("#error").append("ERROR: " + error);
  }
  },
  success: function(request) {
   $("#loading").addClass("hide");
   var t = eval( "(" + request + ")" ) ;
  } // End success
}); // End ajax method

Thanks for the input

Answer 1

Are you sure that response is correct? Parse error mean that there is sth wrong with data being evaluted in line var t = eval( "(" + request + ")" ) ;

Answer 2

Looking at the jQuery source code, there are four returned statuses, in additon to success:

• timeout - when your specified timeout is exceeded
• error - http error, like 404
• notmodified - when requested resource was not modified since last request
• parsererror - when an xml/json response is bad

Answer 3

The second argument that is passed to your error function will either be the string "timeout" "parserror" "error" or "notmodified". The third will be the exception object. This object can be helpful for debugging.

Answer 4

This is an aside, but I think there's a bug in the code you submitted. The line:

 if (error = "timeout") {

should have more equals signs in it:

 if (error == "timeout") {

Answer 5

I find the request more useful than the error.

error:function(xhr,err){
    alert("readyState: "+xhr.readyState+"\nstatus: "+xhr.status);
    alert("responseText: "+xhr.responseText);
}

xhr is XmlHttpRequest.
readyState values are 1:loading, 2:loaded, 3:interactive, 4:complete.
status is the HTTP status number, i.e. 404: not found, 500: server error, 200: ok.
responseText is the response from the server - this could be text or JSON from the web service, or HTML from the web server.