I have the following jQuery get request, which returns html text under the key name "data":
$(".article").click(function() {
$.get("<%= click_path %>", function(data) {
$(".article").html(data);
});
});
All the code executes except the line $(".article").html(data);. In fact, any jquery code I put inside the get request fails to execute, even though it all works fine if I move it outside the get request. Does anyone see anything wrong with my syntax?
jQuery's $.get method is an alias to $.ajax with an assumed HTTP request method of GET and without the ability to specify many options. You give it a URL and a function to run on successfully retrieving that URL. It tries to GET that URL and, if it can, the success function will run. If it can't, or if something is wrong with the response data, it fails silently and will not run the given function.
That being the case, I would assume your request is failing somewhere.
You need to look in the developer's console for errors and to inspect the request.
You can also change your code to use $.ajax and pass in the options, along with your current params, an error method. If the error method is called, you'll receive as params the jqXHR instance, a string textStatus, and a string errorThrown. Pass these into console.log and look at them for clues as to what is wrong as well.
$(".article").click(function() {
$.ajax({
url: "<%= click_path %>",
success: function(data) {
$(".article").html(data);
},
error: function (jqXHR, textStatus, errorThrown) {
console.log(textStatus);
console.log(errorThrown);
}
});
});
Chances are, your ajax request fails to execute and as result, your jQuery code inside the callback never runs.
Run the following instead and see if an error is alerted:
var jqxhr = $.get( "<%= click_path %>", function() {
alert( "success" );
}
.fail(function() {
alert( "error" );
})
.always(function() {
alert( "finished" );
});
Related
Is it possible to catch an error when using JSONP with jQuery? I've tried both the $.getJSON and $.ajax methods but neither will catch the 404 error I'm testing. Here is what I've tried (keep in mind that these all work successfully, but I want to handle the case when it fails):
jQuery.ajax({
type: "GET",
url: handlerURL,
dataType: "jsonp",
success: function(results){
alert("Success!");
},
error: function(XMLHttpRequest, textStatus, errorThrown){
alert("Error");
}
});
And also:
jQuery.getJSON(handlerURL + "&callback=?",
function(jsonResult){
alert("Success!");
});
I've also tried adding the $.ajaxError but that didn't work either:
jQuery(document).ajaxError(function(event, request, settings){
alert("Error");
});
Here's my extensive answer to a similar question.
Here's the code:
jQuery.getJSON(handlerURL + "&callback=?",
function(jsonResult){
alert("Success!");
})
.done(function() { alert('getJSON request succeeded!'); })
.fail(function(jqXHR, textStatus, errorThrown) { alert('getJSON request failed! ' + textStatus); })
.always(function() { alert('getJSON request ended!'); });
It seems that JSONP requests that don't return a successful result never trigger any event, success or failure, and for better or worse that's apparently by design.
After searching their bug tracker, there's a patch which may be a possible solution using a timeout callback. See bug report #3442. If you can't capture the error, you can at least timeout after waiting a reasonable amount of time for success.
Detecting JSONP problems
If you don't want to download a dependency, you can detect the error state yourself. It's easy.
You will only be able to detect JSONP errors by using some sort of timeout. If there's no valid response in a certain time, then assume an error. The error could be basically anything, though.
Here's a simple way to go about checking for errors. Just use a success flag:
var success = false;
$.getJSON(url, function(json) {
success = true;
// ... whatever else your callback needs to do ...
});
// Set a 5-second (or however long you want) timeout to check for errors
setTimeout(function() {
if (!success)
{
// Handle error accordingly
alert("Houston, we have a problem.");
}
}, 5000);
As thedawnrider mentioned in comments, you could also use clearTimeout instead:
var errorTimeout = setTimeout(function() {
if (!success)
{
// Handle error accordingly
alert("Houston, we have a problem.");
}
}, 5000);
$.getJSON(url, function(json) {
clearTimeout(errorTimeout);
// ... whatever else your callback needs to do ...
});
Why? Read on...
Here's how JSONP works in a nutshell:
JSONP doesn't use XMLHttpRequest like regular AJAX requests. Instead, it injects a <script> tag into the page, where the "src" attribute is the URL of the request. The content of the response is wrapped in a Javascript function which is then executed when downloaded.
For example.
JSONP request: https://api.site.com/endpoint?this=that&callback=myFunc
Javascript will inject this script tag into the DOM:
<script src="https://api.site.com/endpoint?this=that&callback=myFunc"></script>
What happens when a <script> tag is added to the DOM? Obviously, it gets executed.
So suppose the response to this query yielded a JSON result like:
{"answer":42}
To the browser, that's the same thing as a script's source, so it gets executed. But what happens when you execute this:
<script>{"answer":42}</script>
Well, nothing. It's just an object. It doesn't get stored, saved, and nothing happens.
This is why JSONP requests wrap their results in a function. The server, which must support JSONP serialization, sees the callback parameter you specified, and returns this instead:
myFunc({"answer":42})
Then this gets executed instead:
<script>myFunc({"answer":42})</script>
... which is much more useful. Somewhere in your code is, in this case, a global function called myFunc:
myFunc(data)
{
alert("The answer to life, the universe, and everything is: " + data.answer);
}
That's it. That's the "magic" of JSONP. Then to build in a timeout check is very simple, like shown above. Make the request and immediately after, start a timeout. After X seconds, if your flag still hasn't been set, then the request timed out.
I know this question is a little old but I didn't see an answer that gives a simple solution to the problem so I figured I would share my 'simple' solution.
$.getJSON("example.json", function() {
console.log( "success" );
}).fail(function() {
console.log( "error" );
});
We can simply use the .fail() callback to check to see if an error occurred.
Hope this helps :)
If you collaborate with the provider, you could send another query string parameter being the function to callback when there's an error.
?callback=?&error=?
This is called JSONPE but it's not at all a defacto standard.
The provider then passes information to the error function to help you diagnose.
Doesn't help with comm errors though - jQuery would have to be updated to also callback the error function on timeout, as in Adam Bellaire's answer.
Seems like this is working now:
jQuery(document).ajaxError(function(event, request, settings){
alert("Error");
});
I use this to catch an JSON error
try {
$.getJSON(ajaxURL,callback).ajaxError();
} catch(err) {
alert("wow");
alert("Error : "+ err);
}
Edit: Alternatively you can get the error message also. This will let you know what the error is exactly. Try following syntax in catch block
alert("Error : " + err);
Mayby this works?
.complete(function(response, status) {
if (response.status == "404")
alert("404 Error");
else{
//Do something
}
if(status == "error")
alert("Error");
else{
//Do something
}
});
I dont know whenever the status goes in "error" mode. But i tested it with 404 and it responded
you ca explicitly handle any error number by adding this attribute in the ajax request:
statusCode: {
404: function() {
alert("page not found");
}
}
so, your code should be like this:
jQuery.ajax({
type: "GET",
statusCode: {
404: function() {
alert("page not found");
}
},
url: handlerURL,
dataType: "jsonp",
success: function(results){
alert("Success!");
},
error: function(XMLHttpRequest, textStatus, errorThrown){
alert("Error");
}
});
hope this helps you :)
I also posted this answer in stackoverflow - Error handling in getJSON calls
I know it's been a while since someone answerd here and the poster probably already got his answer either from here or from somewhere else. I do however think that this post will help anyone looking for a way to keep track of errors and timeouts while doing getJSON requests. Therefore below my answer to the question
The getJSON structure is as follows (found on http://api.jqueri.com):
$(selector).getJSON(url,data,success(data,status,xhr))
most people implement that using
$.getJSON(url, datatosend, function(data){
//do something with the data
});
where they use the url var to provide a link to the JSON data, the datatosend as a place to add the "?callback=?" and other variables that have to be send to get the correct JSON data returned, and the success funcion as a function for processing the data.
You can however add the status and xhr variables in your success function. The status variable contains one of the following strings : "success", "notmodified", "error", "timeout", or "parsererror", and the xhr variable contains the returned XMLHttpRequest object
(found on w3schools)
$.getJSON(url, datatosend, function(data, status, xhr){
if (status == "success"){
//do something with the data
}else if (status == "timeout"){
alert("Something is wrong with the connection");
}else if (status == "error" || status == "parsererror" ){
alert("An error occured");
}else{
alert("datatosend did not change");
}
});
This way it is easy to keep track of timeouts and errors without having to implement a custom timeout tracker that is started once a request is done.
Hope this helps someone still looking for an answer to this question.
I have read similar questions with similar problems but every advice I read seems to be inefficient for me. Here is the ajax call (I am using Jquery 1.9.1):
$( document ).ajaxError(function() {
alert( "AJAX ERROR" );
});
$.post( "/lists/complete", { itemID:id }, function(answer) {
alert("SUCCESS");
}, "text" ).fail( function() {
alert("ERROR");
}).always( function() {
alert("DONE");
});
On the server side the request is received as expected. If I monitor the server response on the client side (using Firebug), I can see that the server sends the 200 response along with the correct data in the body. However, no alert is never triggered !
What can I do to understand the issue ? I must add that I have very little experience with JS and with Jquery...
I'm also not a fan of jquery post. I prefer using $.ajax. However it is recommended to chain done, fail and always.
$.ajax({
url: ' yoururl ',
type: 'POST',
// dataType: 'default: Intelligent Guess (Other values: xml, json, script, or html)',
data: {param1: 'value1'},
})
.done(function() {
console.log("success");
})
.fail(function() {
console.log("error");
})
.always(function() {
console.log("complete");
});
http://api.jquery.com/jQuery.ajax/
Deprecation Notice: The jqXHR.success(), jqXHR.error(), and
jqXHR.complete() callbacks are deprecated as of jQuery 1.8. To prepare
your code for their eventual removal, use jqXHR.done(), jqXHR.fail(),
and jqXHR.always() instead.
I v never been a fan of the $.post i rather use the full ajax call :
$.ajax({
type: 'POST',
url: '/lists/complete',
data: data,
success: function(data){
alert("SUCCESS");
},
error: function(xhr, type, exception) {
// if ajax fails display error alert
alert("ajax error response type "+type);
}
});
Give this a shot and let me know if the alerts go off.
If this doesn't work out, open up the console (firebug...) and go to the network tab, clear it and send your request.
Click on the request and check the headers and response if they are normal.
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 can't figure out what is wrong here.
$(function() {
$('#cars').change(function() {
var cars = $('#cars').val();
$.getJSON('http://fooobar.com/data.php?id='+cars, function(data) {
alert('test');
});
});
});
Request to http://fooobar.com/data.php?id=3 returns json string like this
[{1: "sdadd"}]
The problems is that code
alert('test');
is not executed when request to data.php returns correct json string but is executed when no data is returned.
What I miss ?
[{1: "sdadd"}]
is not a correct JSON string. You can't have numbers as keys in objects and these keys can't start with a number.
That's why jQuery doesn't execute your success callback:
jQuery.getJSON( url [, data] [, success(data, textStatus, jqXHR)] )
According to the documentation:
As of jQuery 1.4, if the JSON file contains a syntax error, the request will usually fail silently
You can try this to check if I'm right:
jQuery.getJSON(...).error(function() { alert("error"); })
I'd guess it's the Same Origin Policy, which stops a webpage calling AJAX on another domain.
You are using incorrect format to do a cross domain data request.
You need to do return JSONP data, not JSON .
For JSONP to work, your URL :
http://fooobar.com/data.php?id=3
which normally returns { "result" : "some data" }
when called with any callback function name ,eg :
http://fooobar.com/data.php?id=3&callback=myJavascriptFunction
should return : myJavascriptFunction( { "result" : "some data" } )
only then it can call your callback javascript function with JSON data.
example:
see the out of these two api calls to facebook api which supports JSONP format :
i) JSON :
https://graph.facebook.com/19292868552
ii) JSONP :
https://graph.facebook.com/19292868552?callback=myFunctionName
Read more here : http://api.jquery.com/jQuery.getJSON/
Same origin policy is the problem here, as others have said.
But here's what they didn't say - how to fix it:
$.ajax({
url: "someurl.com",
dataType: "jsonp",
data: {'some key':'somevalue', 'someotherkey':'val'},
success: function(response) { alert(response); },
error: function(jqXHR, textStatus, errorThrown) {
//do some error handling
alert(jqXHR);
alert(textStatus);
alert(errorThrown);
}
});
Here I'm using the $.ajax method - basically $.getJSON is a wrapper for this with dataType:'json'.
Note: this will change your request so that it passes in a param called "callback" which will be completely random. This needs to be processed by the server and passed back as a function name: i.e
Your request:
someurl.com/?something=something&callback=123456
Should return:
123456({ "key":"value"});
And that should allow you to get the returned data as normal.
Reference:
The bit on JSONP and the various options that can be used in $.ajax is quite good here:
http://api.jquery.com/jQuery.ajax/
Wikipedia has an alright article on it here: http://en.wikipedia.org/wiki/JSONP#Padding
Edit: also doing the request like this and using an error function will allow you to throw any errors to the console or alert boxes, so you can check if your returned JSON is valid or not too. Markup edited to throw an alert box on failure.
I want to know that how can we get ajax status code in jquery.
I have this ajax block:
$.ajax{
type: "GET",
url: "keyword_mapping.html",
data:"ajax=yes&sf="+status_flag,
success: callback.success,
complete: rollup_filters(),
failure: function(){
alert("Failure");
}
}
Now in above code, in case of failure, how can i get ajax status code and some description of that status code ??
You want to use the error option to capture this. For example:
error: function (jqXHR, textStatus, errorThrown)
// Your handler here...
}
You can then use the jqXHR object to retrieve information about the failure.
From the documentation:
For backward compatibility with XMLHttpRequest, a jqXHR object will expose the following properties and methods:
readyState
status
statusText
responseXML and/or responseText when the underlying request responded with xml and/or text, respectively
setRequestHeader(name, value) which departs from the standard by replacing the old value with the new one rather than concatenating the new value to the old one
getAllResponseHeaders()
getResponseHeader()
abort()
First, you have a few syntax errors. The above is a method call, so it needs to follow $.ajax({ ... }); (with parenthesis).
Secondly, you want to supply the error property as part of the object, not failure (see docs for more information).
Third, when you do bind to an error, you are supplied three parameters: jqHXR, textState, errorThrow. These arguments will supply you the details of a failed AJAX call. (More specifically, try jqXHR.status)
Alternatively, you can bind to the $.ajaxError function as well.
Update To keep this more up-to-date, you should now be following the Deferred API (as of jQuery 1.5), which would make binding to an error look something like the following:
$.ajax({ /* options */ })
.done(function( data, textStatus, jqXHR ){
// here you bind to a successful execution.
.fail(function( jqXHR, textStatus, errorThrown ){
// Here you can catch if something went wrong with the AJAX call.
})
.always(function(){
// here you can execute code after both (or either) of
// the above callbacks have executed.
});
Change your failure callback to
error:function (xhr, options, error){
alert(xhr.status);
alert(error);
}
There is nothing like failure in ajax settings. Replace failure by error and you get 3 arguments in the error callback. First argument is the xhr object which has a status property in it.
$.ajax{
type: "GET",
url: "keyword_mapping.html",
data:"ajax=yes&sf="+status_flag,
success: callback.success;
complete: rollup_filters(),
error: function(jqXHR, textStatus, errorThrown){
alert(jqXHR.status);
}
}