The jQuery.ajax() function I use works correctly most of the time. However sometimes it is not returning any data. Instead the error() function is called.
$.ajax({
[...]
, error: function(jqXHR, textStatus, errorThrown) {
console.log(jqXHR);
console.log(textStatus);
console.log(errorThrown);
}
});
I can see in there that in those cases textStatus is 'error' and errorThrown is '' (empty).
The jQuery documentation just lists the possible values of textStatus ("timeout", "error", "abort", and "parsererror"). However it does not describe, what 'error' means.
jqXHR returns an object but it does not seam to reveal any additional insights.
How can I investigate what the source to this issue is?
Found out it happens, whenever Reload is pressed in the browser, while the ajax request was still running.
This post helped me implement a solution.
I would suggest you to use fiddler to monitor the request and analyze what you are getting in response.
Another thing to try is to compose your ajax request in fiddler composer. This way you can figure out whether your are passing all required headers or not.
You will find more details in fiddler.
As KidA said in the comment try this:
console.log(jqXHR.status);
Also, just make sure you are pulling from the right destination (url, listname, etc.) along with the proper data type pull (POST, GET, UPDATE, DELETE, etc.)
I have a huge problem for weeks now, I have to say I don't have a lot of AJAX experience, so it can be an easy problem for someone I hope.
I have an AJAX script, which is used for importing a JSON array from a PHP file and it works fine like 80% of the time.
But sometimes for like 1 hour a day the $ajax part results in an error.
This is my script:
function getData() {
$.ajax({
url: '/php/home.php', //Url to .php file
data: {'data': data}, //Parameter to pass to the .php file, i.e. different query IDs, etc.. - DO NOT REMOVE!
type: 'POST', //Set Ajax to 'POST' type
dataType: 'json', //Tell the return data type to the JS engine
timeout: 10000,
error: function(xhr, status, error) { //If the query fails:
alert('BETA - The cause of error is: ' + xhr.responseText); //v1.1 - display the cause of the error
},
success: function(output) { //If query is successful:
drawChart(output); //Call the chart drawing function, pass the Ajax result as parameter
}
});
}
The referenced PHP file works fine always.
This even got stranger, because I tried to find the cause and the error function gave me the following:
status: error , error: empty , xhr.responsetext: empty
So as I said it works usually, and separate JS files result in an error for the same period of time.
I have already tried the following:
tried with different browsers;
tried to implement noconflicts() before the function;
contacted my hosting and asked if I get somehow limited, not and they don't see any errors in logs either;
tried to debug and it goes to the error;
Do you have any idea what can cause the problem?
Even a hint could help me a lot! Huge thanks to everyone!
I'm having a problem with a page that works fine by itself, but when it's embedded in a iFrame in a corporate webpage (that I don't control) it chokes in IE9 (but not IE8).
The page uses jQuery to make an AJAX call and KnockoutJS to bind content for display. The page passes parameters in a GET request to my server with responds with AJAX, and it seems that it chokes when getting the data back from the server. The data is correct and correctly formatted, however, when this code executes:
$.ajax({
url: this.serviceURL + parameters,
dataType: 'json',
success: callback,
timeout: 3000,
error: function (jqXHR, status, errorThrown) {
if (status == "timeout") {
error("The connection to the server timed out.\nEither the server is down or the network is slow.\nPlease try again later.");
}
else {
error("An error occurred while trying to communicate with the server.\n " + errorThrown);
}
}
});
In IE9, I always hit the "An error occurred..." branch with the errorThrown of "SyntaxError: Invalid character", which tells me nothing.
Anybody got any suggestions on how to go about debugging this problem? I used Fiddler to look at what was being sent to and returned by the server, and everything looks fine on that end.
Update: After sleeping on it for a while, I started fresh today. What I've determined is that for some reason, when my page is iFramed, instead of getting the JSON response:
"{"Foo":true,"Bar":true}"
I'm actually getting (from forcing an error in the error handler so I could inspect the state of the jqXHR.responseText) is:
" {"Foo":true,"Bar":true}"
Which if, using the console, I try feeding to JSON.parse, gives me an error. So the question is, where the heck is that leading space coming from? If I run this in Firefox, I see the correct response from the server (no space) and if I run this outside of the iFrame, I see no leading space. So I don't think it's coming server side. Somewhere in the mess of JS running on the parent page and my page, it's inserting a leading space.
Update 2: A closer examination reveals that jqXHR.responseText.charCodeAt(0) is 65279, so it's not actually a space (although it displays as one) it is the byte order mark. But why is it there now (and not before) and why is it causing a problem?
I couldn't figure out the reason for this problem, so I hacked my way around it by adding a custom converter to my ajax call. So I now have this:
$.ajax({
url: this.serviceURL + parameters,
dataType: 'json',
success: callback,
timeout: 3000,
converters: { "text json": HackyJSONConverter },
error: function (jqXHR, status, errorThrown) {
if (status == "timeout") {
//alert("Timed out");
error("The connection to the server timed out.\nEither the server is down or the network is slow.\nPlease try again later.");
}
else {
error("An error occurred while trying to communicate with the server.\n " + errorThrown);
}
}
});
And my hacky converter looks like this:
function HackyJSONConverter(data) {
if (data[0] = 65279) {
// leading BOM - happens only with an iFrame in OT for some unknown reason
data = data.substring(1);
}
return JSON.parse(data);
}
It's immensely stupid, and I would be delighted if anybody has a better way!
My problem happens to be the error, I am attempting to produce an error, in this case the error being hiding the loading symbol and showing a refresh button in order for the user to reload the page to see if the data loads this time.
$(document).ready(function () {
$('#busy').show();
$(document).bind('deviceready', function () {
var today = $('#todaysong');
$.ajax({
url: 'my url',
dataType: 'jsonp',
jsonp: 'jsoncallback',
timeout: 5000,
success: function (data, status) {
$.each(data, function (i, item) {
var song = '<name>' + item.name + '</name>' + '<artist>' + item.artist + '<br></artist>';
$('#busy').hide();
today.append(song);
});
},
error: function (error) {
$('#busy').fadeOut();
$('#reload').fadeIn();
}
});
});
});
This is my code, could someone advise on what I am doing wrong, I've tried a few things and cannot seem to get it to work, also would I make it so said button was able to refresh this individual piece of code?
Thanks a lot.
In order to debug your code:
Are you generating an error on your own? Is it really an error? Track your request via Firebug or ...
Be sure about running the error function. Again try Firebug or such things to set break points.
Check the JavaScript console for being sure there is no any of damn JavaScript error. And again Firebug error console.
Without seeing other details it is difficult to suggest.
Still I'm trying.. Check the IDs of the elements you have mentioned is same as they are in HTML. Check in HTML that one id is not assigned to more than one element.
In the AJAX code remove jsonp: 'jsoncallback', for a while and test if it is working.
error(jqXHR, textStatus, errorThrown)
A function to be called if the request fails. The function receives
three arguments: The jqXHR (in jQuery 1.4.x, XMLHttpRequest) object, a
string describing the type of error that occurred and an optional
exception object, if one occurred. Possible values for the second
argument (besides null) are "timeout", "error", "abort", and
"parsererror". When an HTTP error occurs, errorThrown receives the
textual portion of the HTTP status, such as "Not Found" or "Internal
Server Error." As of jQuery 1.5, the error setting can accept an array
of functions. Each function will be called in turn. Note: This handler
is not called for cross-domain script and JSONP requests. This is an
Ajax Event.
Where the important part in this case is;
Note: This handler is not called for cross-domain script and JSONP
requests.
Quote from the API documentation of jQuery.ajax.
You should instead be using jsonpCallback.
I am trying to perform this AJAX post but for some reason I am getting a server 500 error. I can see it hit break points in the controller. So the problem seems to be on the callback. Anyone?
$.ajax({
type: "POST",
url: "InlineNotes/Note.ashx?id=" + noteid,
data: "{}",
dataType: "json",
success: function(data) {
alert(data[1]);
},
error: function(data){
alert("fail");
}
});
This is the string that should be returned:
{status:'200', text: 'Something'}
I suspect that the server method is throwing an exception after it passes your breakpoint. Use Firefox/Firebug or the IE8 developer tools to look at the actual response you are getting from the server. If there has been an exception you'll get the YSOD html, which should help you figure out where to look.
One more thing -- your data property should be {} not "{}", the former is an empty object while the latter is a string that is invalid as a query parameter. Better yet, just leave it out if you aren't passing any data.
in case if someone using the codeigniter framework, the problem may be caused by the csrf protection config enabled.
This is Ajax Request Simple Code To Fetch Data Through Ajax Request
$.ajax({
type: "POST",
url: "InlineNotes/Note.ashx",
data: '{"id":"' + noteid+'"}',
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function(data) {
alert(data.d);
},
error: function(data){
alert("fail");
}
});
I just had this problem myself, even though i couldn't find the reason for it in my case, when changing from POST to GET, the problem 500 error disappeared!
type:'POST'
I experienced a similar compound error, which required two solutions. In my case the technology stack was MVC/ ASP.NET / IIS/ JQuery. The server side was failing with a 500 error, and this was occurring before the request was handled by the controller making the debug on the server side difficult.
The following client side debug enabled me to determine the server error
In the $.ajax error call back, display the error detail to the console
error: (error) => {
console.log(JSON.stringify(error));
}
This at least, enabled me to view the initial server error
“The JSON request was too large to be serialized”
This was resolved in the client web.config
<appSettings>
<add key="aspnet:MaxJsonDeserializerMembers" value="150000" />
However, the request still failed. But this time with a different error that I was now able to debug on the server side
“Request Entity too large”
This was resolved by adding the following to the service web.config
<configuration>
…
<system.serviceModel>
<bindings>
<basicHttpBinding>
<binding maxBufferSize="2147483647" maxReceivedMessageSize="2147483647" maxBufferPoolSize="524288">
<readerQuotas maxDepth="32" maxStringContentLength="2147483647"
maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
</binding>
</basicHttpBinding>
</bindings>
The configuration values may require further tuning, but at least it resolved the server errors caused by the ajax post.
You can look up HTTP status codes here (or here), this error is telling you:
"The server encountered an unexpected condition which prevented it from fulfilling the request."
You need to debug your server.
I run into the same thing today. As suggested before get Firebug for Firefox, Enable Console and preview POST response. That helped me to find out how stupid the problem was. My action was expecting value of a type int and I was posting string. (ASP.NET MVC2)
There should be an event logged in the EventVwr (Warning from asp.net), which could provide you more details on where the error could be.
A 500 from ASP.NET probably means an unhandled exception was thrown at some point when serving the request.
I suggest you attach a debugger to the web server process (assuming you have access).
One strange thing: You make a POST request to the server, but you do not pass any data (everything is in the query string). Perhaps it should be a GET request instead?
You should also double check that the URL is correct.
I just face this problem today. with this kind of error, you won't get any responses from server, therefore, it's very hard to locate the problem.
But I can tell you "500 internal server error" is error with server not client, you got an error in server side script. Comment out the code closure by closure and try to run it again, you'll soon find out you miss a character somewhere.
You can also get that error in VB if the function you're calling starts with Public Shared Function rather than Public Function in the webservice. (As might happen if you move or copy the function out of a class). Just another thing to watch for.
Can you post the signature of your method that is supposed to accept this post?
Additionally I get the same error message, possibly for a different reason. My YSOD talked about the dictionary not containing a value for the non-nullable value.
The way I got the YSOD information was to put a breakpoint in the $.ajax function that handled an error return as follows:
<script type="text/javascript" language="javascript">
function SubmitAjax(url, message, successFunc, errorFunc) {
$.ajax({
type:'POST',
url:url,
data:message,
contentType: 'application/json; charset=utf-8',
dataType: 'json',
success:successFunc,
error:errorFunc
});
};
Then my errorFunc javascript is like this:
function(request, textStatus, errorThrown) {
$("#install").text("Error doing auto-installer search, proceed with ticket submission\n"
+request.statusText); }
Using IE I went to view menu -> script debugger -> break at next statement.
Then went to trigger the code that would launch my post. This usually took me somewhere deep inside jQuery's library instead of where I wanted, because the select drop down opening triggered jQuery. So I hit StepOver, then the actual next line also would break, which was where I wanted to be. Then VS goes into client side(dynamic) mode for that page, and I put in a break on the $("#install") line so I could see (using mouse over debugging) what was in request, textStatus, errorThrown. request. In request.ResponseText there was an html message where I saw:
<title>The parameters dictionary contains a null entry for parameter 'appId' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ContentResult CheckForInstaller(Int32)' in 'HLIT_TicketingMVC.Controllers.TicketController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.<br>Parameter name: parameters</title>
so check all that, and post your controller method signature in case that's part of the issue
I found myself having this error to. I had .htaccess redirect configured in a directory. Well it reroutes ajax calls to ofcourse ($.post(../ajax.php)), so it couldn't find the actual file (resulting in 500 error).
I 'fixed' it by placing the ajax.php in a directory (So .htaccess didn't affect).
I was able to find the solution using the Chrome debugger (I don't have Firebug or other third-party tools installed)
Go to developer tab (CTRL+MAJ+I)
Network > click on the request which failed, in red > Preview
It showed me that I had a problem on the server, when I was returning a value which was self-referencing.
In my case it was simple issue, but hard to find. Page directive had wrong Inherits attributes. It just need to include the top level and it worked.
Wrong code
<%# Page Language="C#" CodeBehind="BusLogic.aspx.cs" Inherits="BusLogic"%>
Correct code
<%# Page Language="C#" CodeBehind="BusLogic.aspx.cs" Inherits="Web.BusLogic" %>
When using the CodeIgniter framework with CSRF protection enabled, load the following script in every page where an ajax POST may happen:
$(function(){
$.ajaxSetup({
data: {
<?php echo $this->config->item('csrf_token_name'); ?>: $.cookie('<?php echo $this->config->item('csrf_cookie_name'); ?>')
}
});
});
Requires: jQuery and jQuery.cookie plugin
Sources: https://stackoverflow.com/a/7154317/2539869 and http://jerel.co/blog/2012/03/a-simple-solution-to-codeigniter-csrf-protection-and-ajax
The JSON data you are passing to the server should have same name as you forming in client side.
Ex:
var obj = { Id: $('#CompanyId').val(),
Name: $("#CompanyName").val()
};
$.Ajax(data: obj,
url: "home/InsertCompany".....
If the name is different, ex:
[HttpPost]
public ActionResult InsertCompany(Int32 Id, string WrongName)
{
}
You will get this error.
If you are not passing the data, remove the data attribute from AJAX request.
I had this issue, and found out that the server side C# method should be static.
Client Side:
$.ajax({
type: "POST",
url: "Default.aspx/ListItem_Selected",
data: "{}",
dataType: "json",
contentType: "application/json; charset=utf-8",
success: ListItemElectionSuccess,
error: ListItemElectionError
});
function ListItemElectionSuccess(data) {
alert([data.d]);
}
function ListItemElectionError(data) {
}
Server Side:
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public static String ListItem_Selected()
{
return "server responce";
}
}
As mentioned I think your return string data is very long. so the JSON format has been corrupted.
There's other way for this problem. You should change the max size for JSON data in this way :
Open the Web.Config file and paste these lines into the configuration section
<system.web.extensions>
<scripting>
<webServices>
<jsonSerialization maxJsonLength="50000000"/>
</webServices>
</scripting>
</system.web.extensions>
Use a Try Catch block on your server side and in the catch block pass back the exception error to the client. This should give you a helpful error message.
I also faced the same problem. Here are two ways by which I have solved it-
1. If you're using some framework, make sure you are sending a CSRF token with the ajax call as well
Here is how the syntax will look like for laravel -
<meta name="_token" content="{{ csrf_token() }}">
In your js file make sure to call this before sending the ajax call
$.ajaxSetup({
headers: {
'X_CSRF-TOKEN' : $('meta[name="_token"]').attr('content')
}
});
Another way to solve it would be to change method from post to get
For me, the error was in php file to which i was sending request.
Error was in database connectivity. After fixing the php code, error resolved.
Your code contains dataType: json.
In this case jQuery evaluates the response as JSON and returns a JavaScript object. The JSON data is parsed in a strict manner. Any malformed JSON is rejected and a parse error is thrown. An empty response is also rejected.
The server should return a response of null or {} instead.
I found this occurred in chrome when I did two ajax queries in the jquery 'on load' handler,
i.e. like $(function() { $.ajax() ... $.ajax() ... });
I avoided it using:
setTimeout(function_to_do_2nd_ajax_request, 1);
it's presumably a chrome and/or jquery bug
I had this problem because the page I called ajax post from had EnableViewState="false" and EnableViewStateMac="false" but not the page called.
When I put this on both pages everything started to work. I suspected this when I saw MAC address exception.
Your return string data can be very long.
<system.web>
<compilation debug="true" targetFramework="4.0" />
<httpRuntime maxRequestLength="2147483647" />
</system.web>
For example:
1 Char = 1 Byte
5 Char = 5 Byte
"Hakki" = 5 Byte
I have had similar issues with AJAX code that sporadically returns the "500 internal server error". I resolved the problem by increasing the "fastCGI" RequestTimeout and ActivityTimeout values.
I'm late on this, but I was having this issue and what I've learned was that it was an error on my PHP code (in my case the syntax of a select to the db). Usually this error 500 is something to do using syntax - in my experience. In other word: "peopleware" issue! :D
As an addition to the "malformed JSON" answer, if the query you are running returns an object or anything that prevents the data to be serialised, you will get this error. You should always be sure you have JSON and only JSON at the end of your action method or whatever it is you are getting the data from.
Usually your property is not completely right or something wrong with your server processing.