Develop Reference

ajax post call return 200 but handle error [duplicate]

I have implemented an Ajax request on my website, and I am calling the endpoint from a webpage. It always returns 200 OK, but jQuery executes the error event.
I tried a lot of things, but I could not figure out the problem. I am adding my code below:
jQuery Code
var row = "1";
var json = "{'TwitterId':'" + row + "'}";
$.ajax({
type: 'POST',
url: 'Jqueryoperation.aspx?Operation=DeleteRow',
contentType: 'application/json; charset=utf-8',
data: json,
dataType: 'json',
cache: false,
success: AjaxSucceeded,
error: AjaxFailed
});
function AjaxSucceeded(result) {
alert("hello");
alert(result.d);
}
function AjaxFailed(result) {
alert("hello1");
alert(result.status + ' ' + result.statusText);
}
C# code for JqueryOpeartion.aspx
protected void Page_Load(object sender, EventArgs e) {
test();
}
private void test() {
Response.Write("<script language='javascript'>alert('Record Deleted');</script>");
}
I need the ("Record deleted") string after successful deletion. I am able to delete the content, but I am not getting this message. Is this correct or am I doing anything wrong? What is the correct way to solve this issue?

jQuery.ajax attempts to convert the response body depending on the specified dataType parameter or the Content-Type header sent by the server. If the conversion fails (e.g. if the JSON/XML is invalid), the error callback is fired.
Your AJAX 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.
Your server-side code returns HTML snippet with 200 OK status. jQuery was expecting valid JSON and therefore fires the error callback complaining about parseerror.
The solution is to remove the dataType parameter from your jQuery code and make the server-side code return:
Content-Type: application/javascript
alert("Record Deleted");
But I would rather suggest returning a JSON response and display the message inside the success callback:
Content-Type: application/json
{"message": "Record deleted"}

You simply have to remove the dataType: "json" in your AJAX call
$.ajax({
type: 'POST',
url: 'Jqueryoperation.aspx?Operation=DeleteRow',
contentType: 'application/json; charset=utf-8',
data: json,
dataType: 'json', //**** REMOVE THIS LINE ****//
cache: false,
success: AjaxSucceeded,
error: AjaxFailed
});

I've had some good luck with using multiple, space-separated dataTypes (jQuery 1.5+). As in:
$.ajax({
type: 'POST',
url: 'Jqueryoperation.aspx?Operation=DeleteRow',
contentType: 'application/json; charset=utf-8',
data: json,
dataType: 'text json',
cache: false,
success: AjaxSucceeded,
error: AjaxFailed
});

This is just for the record since I bumped into this post when looking for a solution to my problem which was similar to the OP's.
In my case my jQuery Ajax request was prevented from succeeding due to same-origin policy in Chrome. All was resolved when I modified my server (Node.js) to do:
response.writeHead(200,
{
"Content-Type": "application/json",
"Access-Control-Allow-Origin": "http://localhost:8080"
});
It literally cost me an hour of banging my head against the wall. I am feeling stupid...

I reckon your aspx page doesn't return a JSON object.
Your page should do something like this (page_load)
var jSon = new JavaScriptSerializer();
var OutPut = jSon.Serialize(<your object>);
Response.Write(OutPut);
Also, try to change your AjaxFailed:
function AjaxFailed (XMLHttpRequest, textStatus) {
}
textStatus should give you the type of error you're getting.

I have faced this issue with an updated jQuery library. If the service method is not returning anything it means that the return type is void.
Then in your Ajax call please mention dataType='text'.
It will resolve the problem.

You just have to remove dataType: 'json' from your header if your implemented Web service method is void.
In this case, the Ajax call don't expect to have a JSON return datatype.

See this. It's also a similar problem. Working I tried.
Dont remove dataType: 'JSON',
Note: Your response data should be in json format

Use the following code to ensure the response is in JSON format (PHP version)...
header('Content-Type: application/json');
echo json_encode($return_vars);
exit;

I had the same issue. My problem was my controller was returning a status code instead of JSON. Make sure that your controller returns something like:
public JsonResult ActionName(){
// Your code
return Json(new { });
}

Another thing that messed things up for me was using localhost instead of 127.0.0.1 or vice versa. Apparently, JavaScript can't handle requests from one to the other.

If you always return JSON from the server (no empty responses), dataType: 'json' should work and contentType is not needed. However make sure the JSON output...
is valid (JSONLint)
is serialized (JSONMinify)
jQuery AJAX will throw a 'parseerror' on valid but unserialized JSON!

I had the same problem. It was because my JSON response contains some special characters and the server file was not encoded with UTF-8, so the Ajax call considered that this was not a valid JSON response.

Your script demands a return in JSON data type.
Try this:
private string test() {
JavaScriptSerializer js = new JavaScriptSerializer();
return js.Serialize("hello world");
}

Error thrown while performing ajax call to web api

I have the following basic code. I tried to debug this code but the javascript is very painful to debug, and I do not know where it is failing:
jQuery.support.cors = true;
var packet = {
Image: imageAsString,
PhnType: phoneType,
PhnMdl: phoneManufacturer
};
$.ajax({
url: "https://molecheckerservices2.azurewebsites.net/api/Testing/SubmitTestingData",
type: "POST",
dataType: "json",
data: JSON.stringify({ packet }),
success: function(data, textStatus, xhr) {
alert('yes');
window.localStorage.setItem("dataObject", JSON.stringify(data));
window.location = "results.html";
},
error: function (xhr, textStatus, errorThrown) {
alert('no');
window.localStorage.setItem("dataObject", JSON.stringify([.33, .33, .33]));
window.location = "results.html";
}
it gives me back an alert no, which corresponds with a failure. Additionally as I debug I see in my Javascript console that the error:
Failed to load resource: the server responded with a status of 400 (Bad Request)
Pops up. I tried to look up what this mean but I would be incredibly grateful for any problem specific advice!

Open up Fiddler and manually POST to your endpoint. If you do that, you will see the same error message I saw:
{"message":"No API version was specified in the request, this request needs to specify a ZUMO-API-VERSION of '2.0.0'. For more information and supported clients see: http://go.microsoft.com/fwlink/?LinkId=690568#2.0.0"}
It has a handy-dandy link in there for you. Also, here is a SO answer that possibly applies to you.
I did add the header mentioned above, resent the request and I received that sweet 200 response from your service, so I'm pretty sure that's your issue.
P.S. If you don't want random strangers inserting data into your app like I just did, you should secure your service or at least obfuscate the URL when mentioning it in public.

Jquery generating html codes from C# method

Basically I have a C# web service method that helps to generate HTML code and return it as a string. Now I would like to grab the HTML string from this method and replace a particular div.
function replaceHTML(ID) {
var gID = ID;
$.ajax({
type: "get",
contentType: //what should it be,
url: "the method location",
data: {"ID" : gID },
dataType: //what should it be,
success: function (data) {
$('#Div ID').empty();
$('#Div ID').html(data);
}
});
}
What should be the content Type and data Type? Am I doing it correctly?

Well it all depends on what your web service is providing you and since we cannot see the web service call, we cannot tell you.
In every average web service it should be specified what type of data it communicates with, whether json, xml, or plain text.
Usually though, it will be xml unless something else is specified because web services are SOAP based and are xml formatted, but you should check your web service or share it's code with us.

contentType is the type of data you send to the server, so it'll be application/json in your case. Not nessecary to provide that info though, jQuery will detect it based on the contents of data.
dataType is the type you expect the server to return, so you set it to text/html.
Also, see:
http://api.jquery.com/jquery.ajax/

Hope this will work for you :).
function replaceHTML(ID) {
var gID = ID;
$.ajax({
type: "get",
contentType: 'text',//what should it be,
url: "the method location",
data: JSON.stringify({"ID" : gID }),
dataType: "application/json; charset=utf-8",,
success: function (data) {
$('#Div ID').empty();
$('#Div ID').html(data);
}
}

AJAX requests from jquery in android application to WCF Service always fails

I have an application where I fetch a list of requests made by the user based on the idNo provided. The android application uses AJAX to make a request to a .NET WCF Service which in turn returns a IEnumerable of DTO for that request.
Following is the AJAX Code:
$.ajax({
url: baseURL + "RequestStatusList/"+idNo,
cache : false,
type : "GET",
dataType : "json",
contentType : "application/json; charset=utf-8",
crossdomain : true,
success : function(data, tst, xhr) {
//do something here
},
error: function (xhr, tst, err) {
alert(' Please Try Again ' + xhr.status);
}
});
A similar piece of code works in another page in the application, where only the process in success is different, rest all is same.
Here every time the request fails and enters the error section and displays undefined/0 as error. No details about error, hence i cannot get what maybe the problem.
When I debug the server side code I get proper value in the parameter passed and a IEnumerable is formed and returned. What fails is the client side code after successful execution of server code.
Please Help.
Thanks in advance.

500 - Internal server error. how i can solve it in asp.net MVC 3 on server?

I deployed a mvc 3 project.
The server gave an error 500 - Internal server error. Nothing else.
How can I get more detail about it. How can I know the reason behind it, because there is nothing going wrong in my code in my development machine.
Since I just have FTP access, is there a way for me to create a log and get all the information about the error in detail.
are their any possible thing i can do that i can see the error in my browser. no problem because i deploy on testing domain.

You will get a 500 error if the web.config xml is invalid. Find out if is invalid by opening IIS Manager, and for the site double click on one of the features (Authorization, HTTP Redirect). If the xml is invalid, it will display a message box with an error and a line number.
If the web config is ok, configure customErrors so you can the errors.
http://msdn.microsoft.com/en-us/library/h0hfz6fc(v=vs.100).aspx
This might display some more detailed information.

Please make sure is ASP.Net MVC installed on the server? or Is the correct version of IIS installed on the server?

Check that the data is out of ajax like data_.
var data_ = { indexNum: index };
$.ajax({
type: "POST",
url: "/Home/ExamsById",
data: data_,
dataType: 'json',
success: function (response) {
$(".cont-exams").slideToggle();
}
});

Check that the data is out of ajax like data_.
var data_ = { indexNum: index };
$.ajax({
type: "POST",
url: "/Home/ExamsById",
data: data_,
dataType: 'json',
success: function (response) {
$(".cont-exams").slideToggle();
}
});