recursive ajax or setInterval(), WHICH ONE IS BETTER? - ajax

I am trying to fetch the message table and append the response on the previous fetched results...
here are 2 approaches I have tried, but all failed
1st: recursive fetch
function fetch(){
$.ajax({
url: url,
type: "post",
data:data,
timeout: 3000,
success: function(data){
$(selector).append(data);
setTimeout(function(){fetch()},3000);
}
})
}
2nd: setInterval()
setInterval(function(){fetch()},3000);
function fetch(){
$.ajax({
url: url,
type: "post",
data:data,
timeout: 3000,
success: function(data){
$(selector).append(data);
}
})
}
after few successful ajax call, the browser went frozen and console shows "net::ERR_EMPTY_RESPONSE " OR "ERR_CONNECTION_TIMED_OUT"
please advise
thank you

You may this this if you want to make a recursive call after success or failure
function fetch(url, selector){
$.ajax({
url:url,
type:"post",
data:data,
timeout:3000,
success:function(data){
$(selector).append(data);
fetch();
},
error:function(data){
fetch();
}
});
}

Related

Weird object returned from AJAX request

I have this method:
var chineseCurrency = getChinese();
function getChinese(){
return $.ajax({
context: this,
type: 'GET',
dataType: 'json',
url: "https://www.cryptonator.com/api/ticker/usd-cny"
});
}
That is what printed when console.log(chineseCurrency);:
I am not able to make chineseCurrency equal to "price", so it would be "6.80071377". How can I do that? Tried chineseCurrency.responseText, nope, chineseCurrency['responseText'], nope. Tried to JSON.parse(chineseCurrency), nope. Nothing works!
Sorry if repeated, couldn't find any answer at Stackoverflow.
How do I return the response from an asynchronous call?
Data that is received as response to asynchronous ajax call cannot be returned from the function that calls $.ajax. What you are returning is XMLHttpRequest object (see http://api.jquery.com/jquery.ajax/) that is far from the desired data.
var chineseCurrency = null;
function getChinese(){
return $.ajax({
context: this,
type: 'GET',
dataType: 'json',
url: "https://www.cryptonator.com/api/ticker/usd-cny",
success: function(data) {
alert("success1: chineseCurrency=" + chineseCurrency);
chineseCurrency = data.ticker.price;
alert("success2: chineseCurrency=" + chineseCurrency);
// do what you need with chineseCurrency
}
});
}
You are not taking the data from that is returned from the Ajax call. instead you are just returning the ajax object.
Change your code to :
$.ajax(
{
context: this,
type: 'GET',
dataType: 'json',
url: "https://www.cryptonator.com/api/ticker/usd-cny"
data :{},
error : function(data)
{
console.log('error occured when trying to find the from city');
},
success : function(data)
{
console.log(data); //This is what you should return from the function.
}
});

Keep loading AJAX request

I have an AJAX request which gets data from the database and then populates the page with the data collected. The problem I am having is that currently the ajax request is in a setInterval which is being called every second.
setInterval(function () {
$.ajax({
method: "POST",
url: "/PLM/FetchPageContent",
dataType: "json",
success: function (data) {
console.log(data);
}
});
}, 1000);
This is fetching the data every second which is a huge strain on the server as it's making a request and then I am calling it again even when the data hasn't come through first time.
Is there a way that I can call the same AJAX request over and over but only after it's finished fetching the data first time and not keep going up?
There are better architectures to accomplish this type of scenario (websockets as mentioned in the comments would be one example), but to do strictly what you're asking, sure! Wrap it in a function that calls itself:
function getData(){
$.ajax({
method: "POST",
url: "/PLM/FetchPageContent",
dataType: "json",
success: function (data) {
console.log(data);
getData();
}
});
}
Replace the setInterval with a setTimeout only once you're done:
function fetchAjax() {
$.ajax({
method: "POST",
url: "/PLM/FetchPageContent",
dataType: "json",
success: function (data) {
console.log(data);
setTimeout(fetchAjax, 1000);
}
});
};
Add a variable to distunguish if ajax call is already underway. If it is, don't do anything. If not, go ahead.
var isAjaxInProgress = false;
setInterval(function () {
if (!isAjaxInProgress){
isAjaxInProgress = true;
$.ajax({
method: "POST",
url: "/PLM/FetchPageContent",
dataType: "json",
success: function (data) {
console.log(data);
isAjaxInProgress = false;
}
});
}
}, 1000);

Ajax post parameters ASP.NET MVC 3

Hello guys i have the next ajax call for login. I serialize the form and send the data to server and return redirect url link. My problem is that my url after post is like
http://localhost:50802/?username=&password= and not http://localhost:50802/Home
$.ajax({
type: "POST",
url: "Login/Login",
dataType: 'json',
contentType: "application/json; charset=utf-8",
data: loginJson,
cache: true,
async: false,
complete: function (result) {
alert(result.link);
window.location.replace = "/Home/Index";
},
error: function () {
$("#username").val("");
$("#password").val("");
alert("Wrong Username or Password!");
}
}); //end ajax call
It looks like you wrote this $.ajax call in the .click event of a submit button or in the .submit event of a form without canceling the default action by returning false from the callback or by calling preventDefault on the argument. Here's how your code should look like:
$('#id_of_your_form').submit(function(e) {
e.preventdefault(); // <-- That's what I am talking about and what you forgot
$.ajax({
type: "POST",
url: "Login/Login",
dataType: 'json',
contentType: "application/json; charset=utf-8",
data: loginJson,
cache: true,
async: false,
complete: function (result) {
window.location.replace = "/Home/Index";
},
error: function () {
$("#username").val("");
$("#password").val("");
alert("Wrong Username or Password!");
}
}); //end ajax call
});
Also async: false,????? You know what this does, do you? That's not AJAX. That's a blocking synchronous call to your webserver during which the client browser would be frozen like during the Ice Age 2 ruining all user experience.
Try returning false at the end of your submit function
$('#id_of_your_form').submit(function(e) {
$.ajax({
type: "POST",
url: "Login/Login",
dataType: 'json',
contentType: "application/json; charset=utf-8",
data: loginJson,
cache: true,
async: false,
complete: function (result) {
window.location = "/Home/Index";
},
error: function () {
$("#username").val("");
$("#password").val("");
alert("Wrong Username or Password!");
}
}); //end ajax call
return false; });
Another option would of course be to return the correct redirectlink from the controller instead of overriding it in the java script.

Return ajax data [duplicate]

This question already has answers here:
How do I return the response from an asynchronous call?
(41 answers)
Closed 7 years ago.
I have an ajax call in a function and I did not find a solution how to return the data:
function get_blog_post(id){
var info="id="+id;
$.ajax({
type: 'POST',
url: 'get_blog_post.php',
data: info,
success: function(data){
return data;
}
});
}
The code above doesn't works. The data contains the right answer but I can't use it if I callthe get_blog_post() function.
:\
function get_blog_post(id, callback){
var info="id="+id;
$.ajax({
type: 'POST',
url: 'get_blog_post.php',
data: info,
success: function(data){
callback(data);
}
});
}
get_blog_post(5, function(data){
// use data here
});
OR set async = false (not recommended):
$.ajax({
type: 'POST',
url: 'get_blog_post.php',
data: info,
async: false,
success: function(data){
return data;
}
});
The success function runs some time after the ajax call completes. That's the nature of asynchronous calls--like ajax in javascript.
That means you cant return it and have to do something with the data in that function. Perhaps it is text and you put it into a text area like:
success: function(data){
$('textarea').val(data);
}
Provide a callback method and do what ever you want to do inside it
function get_blog_post(id, callback){
var info="id="+id;
$.ajax({
type: 'POST',
url: 'get_blog_post.php',
data: info,
success: callback
});
}

Get response from url using ajax and jquery

want to get response from url using ajax and jquery.
tried with this code
$(document).ready(function () {
$.ajax({
type: 'POST',
url: 'apexweb.co.in/apex_quote/uname_validation.asp?,
dataType:'jsonp',
success: function(data){
alert(data);
}
});
});
i want to display response as fail but i didn't get any response on browser
Help Me
Try this
$(document).ready(function () {
$.ajax({
type: "POST",
url: "apexweb.co.in/apex_quote/uname_validation.asp?",
contentType: "application/json; charset=utf-8",
dataType: "jsonp",
success: function (data) {
alert(data.d);
},
failure: function (data) {
alert(data.d);
}
});
});

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