Develop Reference

ajax jquery update page without refreshing

I currently have the below function which updates the data in a div when the page is refreshed and this works fine however i want to edit the function to make it constantly update say every 2 seconds without having to refresh the page. How would i go about doing this?
<script>
$(document).ready(function ajaxLoop() {
//-----------------------------------------------------------------------
// Send a http request with AJAX Jquery
//-----------------------------------------------------------------------
$.ajax({
url: 'getOrderStatus.php', // Url of Php file to run sql
data: "",
dataType: 'json', //data format
success: function ajaxLoop(data) //on reciept of reply
{
var OrdersSubmitted = data[0].SUBMITTED; //get Orders Submitted Count
var OrdersFulfilled = data[0].FULFILLED; //get Orders Fulfilled count
//--------------------------------------------------------------------
// 3) Update html content
//--------------------------------------------------------------------
$('#OrdersSubmitted').html("SUBMITTED:" + OrdersSubmitted);
$('#OrdersFulfilled').html("FULFILLED:" + OrdersFulfilled); //Set output html divs
}
});
});
</script>

You can chain setTimeout calls to achieve this:
$(document).ready(function() {
function updateOrders() {
$.ajax({
url: 'getOrderStatus.php',
dataType: 'json',
success: function ajaxLoop(data) {
var OrdersSubmitted = data[0].SUBMITTED;
var OrdersFulfilled = data[0].FULFILLED;
$('#OrdersSubmitted').html("SUBMITTED:"+ OrdersSubmitted);
$('#OrdersFulfilled').html("FULFILLED:"+ OrdersFulfilled);
setTimeout(updateOrders, 2000);
}
});
});
The alternative is setInterval(), however if the requests slow down this can lead to calls being queued, which will eventually lead to memory issues.

You need to add a repeating event to call your updateOrders function. Like:
function startUpdateOrdersTimes() {
setInterval(function() {
updateOrders();
}, 2000);
//Call now (otherwise waits for first call)
updateOrders();
}

Using "window.setInterval" (https://developer.mozilla.org/en/docs/Web/API/window.setInterval) you can repeatedly execute a function at a specified time interval.
function SomeFunction()
{
$.ajax({...});
}
window.setInterval(SomeFunction,2000);
This would execute SomeFunction every 2 seconds
Hope this helps

timerupdateorders = setInterval(function() {
ajaxLoop();
}, 2000);
You may use
clearInterval(timerupdateorders);
to end the timer

Function.prototype.apply: Arguments list has wrong type

The error in the title of the post came from jQuery version 1.10.2, line 637
I've got a modal that pops up on a button click with some textboxes and when a button inside the modal is clicked, the information that's in the text boxes is added to a database via AJAX. In order to make the page a little more user-friendly I added a setTimeout function to pause the hiding of the modal so the user can see a verification message that the data was added to the database. Block 1 of my code adds the record to the database, but the setTimeout call doesn't work right:
function insert(data) {
data = JSON.stringify(data);
$.ajax({
type: "POST",
url: "../Service.asmx/InsertPerson",
dataType: "json",
contentType: "application/json",
data: data,
//record gets added to the database
//something about the setTimeout function
//that gives the error in the title
success: function () {
console.log('success before setTimeout');
var successMessage = $('<div>').text('Successfully added to the database...').css('color', 'green');
$('.modal-body').append(successMessage);
//*******this function doesn't run
window.setTimeout(function () {
$('#contact').modal('hide');
$('.modal-body input').each(function () {
$(this).val('');
}, 1000);
});
}
});
}
I fixed it using the code:
(the success function is what we need to pay attention to here)
function insert(data) {
data = JSON.stringify(data);
$.ajax({
type: "POST",
url: "../Service.asmx/InsertPerson",
dataType: "json",
contentType: "application/json",
data: data,
//record gets added to the database
success: function () {
console.log('success before setTimeout');
var successMessage = $('<div>').text('Successfully added to the database...').css('color', 'green');
$('.modal-body').append(successMessage);
window.setTimeout(function () {
$('.modal-body input').each(function () {
$(this).val('');
});
$('#contact').modal('hide');
}, 1000);
}
});
}
I see that I in the first block I didn't close the each function, and I fixed that in the second block and that's why it works, but for future reference, what does this error really MEAN in this context?

It means that you left off the second argument to setTimeout and instead passed it as the second argument to .each().
edit — it looks like jQuery is picking up the argument (that 1000) and trying to pass it through to its internal each implementation. The .apply() function expects it to be an array.

make sure ajax request doesn't get fired multiple time

I was working on a simple form page and I was wondering what happens if someone clicks the submit button many many times (incase my shared hosting somehow seems to be slow at that time).
Also, incase anyone wants to look at my code
$.ajax({
url: "submit.php",
type: 'POST',
data: form,
success: function (msg) {
$(".ressult").html("Thank You!");
},
error: function () {
$(".result").html("Error");
}
});
Is there a way to make it so after the user clicks it once, it won't run it again until the first click is done?
Thank you

You can use jQuery's .one() function:
(function handleSubmit() {
$('#submitBtn').one('click', function() {
var $result = $('.result');
$.ajax({
url: 'submit.php',
type: 'POST',
data: form,
success: function (msg) {
$result.html('Thank You!');
handleSubmit(); // re-bind once.
},
error: function () {
$result.html('Error');
}
}); // End ajax()
}); // End one(click)
}()); // End self-invoked handleSubmit()
*Edit: * Added recursion for multiple submissions.

Use a boolean flag
if (window.isRunning) return;
window.isRunning = true;
$.ajax({
url:"submit.php",
type: 'POST',
data: form,
success: function (msg){
$(".ressult").html("Thank You!");
},
error: function (){
$(".result").html("Error");
},
complete : function () {
window.isRunning = false;
}
});

var $button = $(this);
$button.prop('disabled', true); // disable the button
$.ajax({
url:"submit.php",
type: 'POST',
data: form,
success: function (msg){
$(".ressult").html("Thank You!");
},
error: function (){
$(".result").html("Error");
},
complete: function() {
$button.prop('disabled', false); // enable it again
}
});

Have you considered replacing your submit button with a loader image while the query executes, then re-adding it once the query is complete?
EDIT: Using the loader image is a sort of universal "I'm doing something" indicator, but disabling the button would work too!

You could disable the submit button, before the ajax call is made. And then, if required, enable it on success.

AJAX doesn't automatically update before button is pressed

I'm making a conversation system where 2 people can chat with each other. I've made an AJAX function which updates the DIV box containing the messages every 2 seconds.
This is working as intended, after a user have written a message. Why isn't the AJAX call being run right away?
// SET AUTORUN updateMessages() EVERY 2 SECONDS
$(document).ready(function() {
var interval
window.onload = function(){
interval = setInterval('updateMessages()', 2000);
};
});
// UPDATE #mail_container_conversation
function updateMessages() {
$.ajax({
type: "POST",
url: "<?php echo site_url(); ?>mail/ajaxupdate/<?php echo $user; ?>",
data: dataString,
 
success: function(data){
$("#mail_container_conversation").html(data);
}
});
}
// SEND NEW MESSAGE
$(function(){
$("#mail_send").submit(function(){
dataString = $("#mail_send").serialize();
 
$.ajax({
type: "POST",
url: "<?php echo site_url(); ?>mail/send",
data: dataString,
 
success: function(data){
updateMessages();
$(".mail_conversation_answer_input").val('');
}
 
});
 
return false;
});
});

You should provide functions instead of strings to setTimeout/setInterval functions. And also there's no need for you to set interval on window load event. You can just keep it as part of DOM ready:
$(function() {
updateMessages(); // don't wait 2 seconds for first update
setInterval(updateMessages, 2000); // update every 2 seconds
});
Everything else seems to should work as expected as long as your posback work when no data is being received (ref dataString).
I hope you do realise that you're using implied globals and understand why that may be a big problem (ref dataString again).
How I would rewrite your code
I would rewrite your whole code into the following that removes implied global variable dataString, doesn't pollute global scope with additional functions and uses setTimeout instead of interval which may in some cases be problematic (although in your case since it' only runs every 2 seconds it shouldn't be a problem if there's no additional very complex client-side script execution)
I've kept everything within function closure local scope:
$(function() {
var timeout = null;
var form = $("#mail_send").submit(function(evt){
evt.preventDefault();
$(".mail_conversation_answer_input", form).val("");
updateMessages();
});
var updateMessages = function() {
// we don'w want submit to interfere with auto-updates
clearTimeout(timeout);
$.ajax({
type: "POST",
url: "<?php echo site_url(); ?>mail/send",
data: form.serialize(),
success: function(data){
$("#mail_container_conversation").html(data);
timeout = setTimeout(updateMessages, 2000);
}
});
};
// start updating
updateMessages();
});
This code requires your server side (processing on /mail/send) to understand that when nothing is being posted (no data) that it doesn't add empty line in the conversation but rather knows that this is just an update call. This functionality now uses only one server-side URL and not two of them. If you'd still require two, then this code should do the trick:
$(function() {
var timeout = null;
var url = {
update: "<?php echo site_url();?>mail/ajaxupdate/<?php echo $user;?>",
submit: "<?php echo site_url();?>mail/send",
use: "update"
};
var form = $("#mail_send").submit(function(evt){
evt.preventDefault();
url.use = "submit";
$(".mail_conversation_answer_input", form).val("");
updateMessages();
});
var updateMessages = function() {
// we don'w want submit to interfere with auto-updates
clearTimeout(timeout);
$.ajax({
type: "POST",
url: url[url.use],
data: form.serialize(),
success: function(data){
$("#mail_container_conversation").html(data);
url.use = "update";
timeout = setTimeout(updateMessages, 2000);
}
});
};
// start updating
updateMessages();
});

If the rest of your code work, the problem probably is withing this code:
$(document).ready(function() {
var interval
window.onload = function(){
interval = setInterval('updateMessages()', 2000);
};
});
There is no need to attach it to window.onload, since you already wrapped it in a DOM-ready callback.
Remove the single-quotes and the parenthesis from within your call to setInterval
The DOM-ready callback can be shorten, by just passing a function to the jQuery-method.
Try this instead:
$(function () {
setInterval(updateMessages, 2000);
});
Further improvements - Avoid intervals with AJAX:
When dealing with AJAX, you should avoid using intervals, as you may end up stacking calls to the server, if the server takes more than two seconds to respond. setInterval will not care if your server had time to respond or not, it will keep calling it every 2 seconds no matter what.
I suggest that you use a timeout instead, and start a new timeout in the complete-callback of the Ajax-call.
In your case, it could look something like this:
$(function () {
// Make the first call immediately when the DOM is ready
updateMessage();
});
function updateMessages() {
$.ajax({
type: "POST",
url: "<?php echo site_url(); ?>mail/ajaxupdate/<?php echo $user; ?>",
data: dataString,
success: function(data){
$("#mail_container_conversation").html(data);
// Make a new call, 2 seconds after you've
// received a successful respose
setTimeout(updateMessages, 2000);
}
});
}

The problem is that updateMessages() tries to send datastring to the server, but this doesn't get filled in until the .submit() function runs.
I don't know what you should put in there, since I don't know what the mail/ajaxupdate script expects. If this is called when nothing happens, I suspect no form data is needed at all, so you can give an empty string.
I'll bet if you checked the Javascript console you'd see some error messages about trying to serialize undefined.

give a try with
$(document).ready(function() {
setInterval('updateMessages()', 2000);
});

You don't need the window.onload in your document ready call.
$(document).ready(function() {
setInterval('updateMessages()', 2000);
});
That should be enough to get it started.
As it is now, once the DOM is ready, you're then asking it to wait for the window to load.. but by that point it's already loaded, so nothing happens.

jquery click event

I have some jquery that looks like this,
$('.career_select .selectitems').click(function(){
var selectedCareer = $(this).attr('title');
$.ajax({
type: 'POST',
url: '/roadmap/step_two',
data: 'career_choice='+selectedCareer+"&ajax=true&submit_career=Next",
success: function(html){
$('.hfeed').append(html);
$('#grade_choice').SelectCustomizer();
}
});
});
My problem is that if the user keeps clicking then the .hfeed keeps getting data appended to it. How can I limit it so that it can only be clicked once?

Use the one function:
Attach a handler to an event for the elements. The handler is executed at most once per element
If you wanted the element to only be clicked once and then be re-enabled once the request finishes, you could:
A) Keep a state variable that updates if a request is currently in progress and exits at the top of the event if it is.
B) Use one, put your code inside a function, and rebind upon completion of request.
The second option would look like this:
function myClickEvent() {
var selectedCareer = $(this).attr('title');
var that = this;
$.ajax({
type: 'POST',
url: '/roadmap/step_two',
data: 'career_choice='+selectedCareer+"&ajax=true&submit_career=Next",
success: function(html){
$('.hfeed').append(html);
$('#grade_choice').SelectCustomizer();
},
complete: function() {
$(that).one('click', myClickEvent);
}
});
}
$('.career_select .selectitems').one('click', myClickEvent);

You can either use a global variable like
var added = false;
$('.career_select .selectitems').click(function(){
if(!added) {
// previous code here
added = true;
}
});
or use .one("click", function () { ... }) instead of the previous click function to execute the handler at most once per element. See http://api.jquery.com/one/ for more details.