In above ajax call the object jData returns null .. but returns the object successfully if displayed with success:
var jData = null;
function x() {
$.ajax({
url : 'http://...",
success : function(data) {
jData = data;
alert(jData); // displays the object
}
});
return jData; //returns null ??
};
$.ajax() is asynchronous. You have to work with jData directly in success callback
var jData = null;
function x() {
$.ajax({
url : "http://...",
success : function(data) {
jData = data;
alert(jData); // displays the object
//do stuff here
}
});
}
Your are getting the data out of the scope of your block , that for very reason it not occuring ,, return your jdata inside the success operation
Ajax is asynchronous, you need to return jdata from inside the success callback. Otherwise when you return jdata, the ajax call has not yet returned and jdata has not been assigned a value.
Related
I am working on the jquery to call a function to get the return value that I want to store for the variable email_number when I refresh on a page.
When I try this:
function get_emailno(emailid, mailfolder) {
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
email_number = data;
}
});
return email_number;
}
I will get the return value as 6 as only when I use alert(email_number) after the email_number = data;, but I am unable to get the value outside of a function.
Here is the full code:
var email_number = '';
// check if page refreshed or reloaded
if (performance.navigation.type == 1) {
var hash = window.location.hash;
var mailfolder = hash.split('/')[0].replace('#', '');
var emailid = 'SUJmaWg4RTFRQkViS1RlUzV3K1NPdz09';
get_emailno(emailid, mailfolder);
}
function get_emailno(emailid, mailfolder) {
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
email_number = data;
}
});
return email_number;
}
However, I have been researching and it stated that I would need to use callback via ajax but I have got no idea how to do this.
I have tried this and I still don't get a return value outside of the get_emailno function.
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
async: true,
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
email_number = data;
}
});
I am getting frustrated as I am unable to find the solution so I need your help with this. What I am trying to do is I want to call on a get_emailno function to get the return value to store in the email_number variable.
Can you please show me an example how I could use a callback function on ajax to get the return value where I can be able to store the value in the email_number variable?
Thank you.
From the jquery documentation, the $.ajax() method returns a jqXHR object (this reads fully as jquery XMLHttpRequest object).
When you return data from the server in another function like this
function get_emailno(emailid, mailfolder) {
$.ajax({
// ajax settings
});
return email_number;
}
Note that $.ajax ({...}) call is asynchronous. Hence, the code within it doesn't necessarily execute before the last return statement. In other words, the $.ajax () call is deferred to execute at some time in the future, while the return statement executes immediately.
Consequently, jquery specifies that you handle (or respond to) the execution of ajax requests using callbacks and not return statements.
There are two ways you can define callbacks.
1. Define them within the jquery ajax request settings like this:
$.ajax({
// other ajax settings
success: function(data) {},
error: function() {},
complete: function() {},
});
2. Or chain the callbacks to the returned jqXHR object like this:
$.ajax({
// other ajax settings
}).done(function(data) {}).fail(function() {}).always(function() {});
The two methods are equivalent. success: is equivalent to done(), error: is equivalent to fail() and complete: is equivalent to always().
On when it is appropriate to use which function: use success: to handle the case where the returned data is what you expect; use error: if something went wrong during the request and finally use complete: when the request is finished (regardless of whether it was successful or not).
With this knowledge, you can better write your code to catch the data returned from the server at the right time.
var email_number = '';
// check if page refreshed or reloaded
if (performance.navigation.type == 1) {
var hash = window.location.hash;
var mailfolder = hash.split('/')[0].replace('#', '');
var emailid = 'SUJmaWg4RTFRQkViS1RlUzV3K1NPdz09';
get_emailno(emailid, mailfolder);
}
function get_emailno(emailid, mailfolder) {
$.ajax({
url: 'getemailnumber.php',
type: 'POST',
data : {
emailid: emailid,
mailfolder: mailfolder
},
success: function(data)
{
// sufficient to get returned data
email_number = data;
// use email_number here
alert(email_number); // alert it
console.log(email_number); // or log it
$('body').html(email_number); // or append to DOM
}
});
}
I'm need some help figuring out how to get back data from the second ajax call, not the first.
I have this method that calls my ajax calls
var projectWithIssues = getProjects().done(function(result) {
....
}
When I look at the results from this, I get back the results on my first ajax call(getEnt_PodType().done()). I want to get the results from the second ajax call within getProjects(). I understand the reason I'm getting the first results back is because I have the return on the first ajax call. However, If I don't have a return there. I get a undefined on the line above. How can I return the data from the second call?
function getEnt_PodType() {
var ent_PodType;
var oDataUrl = //URL to my data;
return $.ajax({
url: oDataUrl,
type: "GET",
async: true,
beforeSend: function (xhr) {
xhr.setRequestHeader("ACCEPT", accept);
},
success: function (xhr, textStatus) {
}
});
}
function getProjects() {
return getEnt_PodType().done(function (res) {
var ent_PodType;
if (res.d.results != undefined) {
ent_PodType = res.d.results[0].Ent_PodType;
}
console.log("The ent pod type value is " + ent_PodType);
var QUERY_FILTER =
"$filter=Ent_PodType eq '" + ent_PodType + "'";
var url = restUrl + QUERY_FILTER;
// I want to return the results from this ajax call
$.ajax({
url: url,
type: "GET",
async: true,
beforeSend: function (xhr) {
xhr.setRequestHeader("ACCEPT", accept);
},
success: function (xhr, textStatus) {
//projects = parseODataResultTest(xhr);
//return projects;
}
});
});
}
Thanks in advance!
Try utilizing pattern found at deferred.then
// first request
var request = $.ajax(url1),
chained = request.then(function( data ) {
console.log(data) // first request response data
// return second request
return $.ajax(url2)
});
chained.then(function( data ) {
console.log(data) // second request response data
// data retrieved from url2 as provided by the first request
});
var request = $.ajax("https://gist.githubusercontent.com/guest271314/23e61e522a14d45a35e1/raw/62775b7420f8df6b3d83244270d26495e40a1e9d/ticker.json"), // first request , `html` document
chained = request.then(function( data ) {
console.log(data) // `["abc"]`
// return `data` from second request
return $.ajax("https://gist.githubusercontent.com/guest271314/6a76aa9d2921350c9d53/raw/49fbc054731540fa68b565e398d3574fde7366e9/abc.txt")
});
chained.then(function( data ) {
console.log(data) // `abc123`
// data retrieved from url2 as provided by the first request
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
Use .then instead of .done, it allows better chaining of functions.
Break your code apart so that the two AJAX calls are in separate functions, and have both those functions return the result of their $.ajax call. You can then use:
func1().then(func2).then(...);
func2 will be passed the result of the first AJAX call, and then the result of that will be passed to whatever function is in the final then.
In your case you can also put the call to parseODataResultTest in the chain and then the final function will (eventually) be called with the required data, i.e.:
getEnt_PodType().then(getProjects).then(parseODataResultTest).then(function(projects) {
// use projects here, and _only_ here because it won't
// be in scope or defined anywhere else
...
});
I am doing an Ajax request on an XML file and mapping the XML into a JavaScript object my problem is that am logging the object and seeing the values I won't but when I try to return the values I keep getting undefined, even that all the code is inside the success callback of the AJAX request, my code is as bellow:
// Errors Object
var ErrorsObject = {};
var ErrorApplet = $('.AppletStyle1 table td');
// Ajax Request
$.ajax({
type: "GET",
url: "ECA_ADMIN_IO.xml",
dataType: "xml",
cache: false,
success: function (xml) {
$(xml).find('EcaAdminBc').each(function () {
var code = $(this).find('code').text();
var msg = $(this).find('msg').text();
ErrorsObject[code] = msg;
});
// Reformat Errors
if(ErrorApplet.length > 0) {
$(ErrorApplet).each(function(){
var Error = $(this).text();
if(Error.indexOf("SBL") >= 0){
var ErrorCode = Error.split('(')[1].replace(")","");
var ErrorText = ErrorsObject[ErrorCode];
// The Log is showing the values correctly but i cant access the object values
console.log(ErrorsObject);
// ErrorText And ErrorCode Are always undefined !!
if(typeof ErrorText != 'undefined'){
$(this).text(ErrorText);
}
}
});
}
}
});
I need additional context, but I guess what the problem is. You are trying to do some thing like this:
var myFunction = function(){
// Error Object
var ErrorsObject = {};
var ErrorApplet = $('.AppletStyle1 table td');
$.ajax(
type: "GET",
url: "ECA_ADMIN_IO.xml",
dataType: "xml",
cache: false,
success: function (xml) {
//using response to fill ErrorsObject
ErrorsObject['Ok'] = 'This key has Value!';
//more awesome code here
//... lets check again:
console.log(ErrorsObject['OK']); //Outputs 'This key has Value!'
}
);
return ErrorsObject;
};
var myAwesomeErrorObject = myFunction();
console.log(myAwesomeErrorObject['OK']); //undefined!
console.log(myAwesomeErrorObject); //Empty object!
The problem is that myFunction finished before the success callback function gets executed (the callback is asynchronous). That is why logging myAwesomeErrorObject['OK'] shows undefined. I guess that you also tried return ErrorsObject inside the success callback, but that won't work either.
In order to fix your code you must either:
Use the ErrorsObject inside the success callback (i.e. don't return it).
Call a second function from inside the success callback, passing it the ErrorsObject.
Pass a calback function to myfunction and execute it from inside the success callback.
I have a simple ajax function
function get_country(request_term) {
var country_list = '';
$.ajax({
url : "activity/get_country",
type : "POST",
cache : false,
data : {
request_term : request_term
},
success : function(data) {
if(data != '') {
country_list = $.parseJSON(data);
alert(country_list); ----> Got value here
}
}
});
alert(country_list); ----> Not getting value here
return country_list;
}
the problem is, i'm getting the data in the success function, but unable to return it from the main function.
Because ajax is asynchronous, you can't know when the success function will complete (or if it will ever complete). Therefore any code that requires the result of the ajax call must depend on the ajax callback too.
jQuery makes it very easy to bind additional callbacks.
return $.ajax({ /* rest of your code */
get_country(request_term).done(function (data) {
//are you sure JSON isn't returned already?
country_list = $.parseJSON(data);
});
You can do it by making async as false. But it is not a recommented way.
This code will return country_list
function get_country(request_term) {
var country_list = '';
$.ajax({
url : "activity/get_country",
type : "POST",
cache : false,
async : false,
data : {
request_term : request_term
},
success : function(data) {
if(data != '') {
country_list = $.parseJSON(data);
alert(country_list);
}
}
});
alert(country_list);
return country_list;
}
Once again having problems being a new to javascript. I want to get the reply from my PHP script using JQuery's get. Here's my function
function getNext(){
var returnData = null;
$.get("get.php", {task:'next'}, function(responseText){
returnData = responseText; }, "text");
return returnData;
}
Now obviously the function returns null even though the request was successful. Why?
Thanks for your help in advance.
Because ajax is asynchronous, it acts independently on its own and so by the time the return statement completes, it hasn't been assigned yet.
function getNext(){
var returnData;
$.ajax({
url: "get.php",
data: {task:'next'},
success: function(responseText) { returnData = responseText },
async: false;
});
return returnData;
}
Note that this may "freeze" the UI because Javascript is single threaded -- it will wait until it receives the response from the server.
You may want to refactor it so that the action is called in the success callback. Could you show us what triggers the invokation of the getNext method?
try this
function getNext(){
var returnData = null;
$.get("get.php", {task:'next'},
function(responseText){
returnData = responseText;
alert('Data ' + responseText);
});
}
You will have to poll whether returnData contains actual data that you want periodically (or put your code into the callback method)