jQuery AJAX Tutorial, Example: Simplify Ajax development with jQuery
- By Viral Patel on April 12, 2009
jQuery, the JavaScript library provides some powerful set of jQuery AJAX API’s to handle AJAX requests. The normal way of making AJAX calls using JavaScript is a bit odd as you have to first create an XMLHttpRequest object that depends on the browser and then make an AJAX call. Also sending a form data using AJAX is also bit difficult if we use normal JavaScript approach of calling AJAX.
jQuery provides simple yet powerfull functions which have extended the JavaScript AJAX methods and provide more flexible way. Let us see different ways of doing AJAX things in jQuery.
GET Request method using jQuery
Load a remote page using HTTP GET request method. This is an easy way to send a simple GET request to a server. It allows a single callback function to be specified that will be executed when the request is complete (and only if the response has a successful response code).
jQuery.get( url, [data], [callback], [type] )
url: (String) The URL of the page to load.
data (Optional): (Map) Key/value pairs that will be sent to the server.
callback (Optional): (Function) A function to be executed whenever the data is loaded successfully.
type (Optional): (String) Type of data to be returned to callback function: “xml”, “html”, “script”, “json”, “jsonp”, or “text”.
e.g.
$.get(
"http://some-remote-site",
"{key:value}",
function(data) { alert(data); },
"html"
);
$.get(
"http://some-remote-site",
function(data) { alert(data); },
);
POST Request method using jQuery
Sending post method is also very easy with jQuery. All you have to do is just to call jQuery.post () method instead of jQuery.get (). Following is the syntax of post method.
jQuery.post( url, [data], [callback], [type] )
url: (String) The URL of the page to load.
data (Optional): (Map) Key/value pairs that will be sent to the server.
callback (Optional): (Function) A function to be executed whenever the data is loaded successfully.
type (Optional): (String) Type of data to be returned to callback function: “xml”, “html”, “script”, “json”, “jsonp”, or “text”.
$.post("test.php", { func: "getNameAndTime" },
function(data){
alert("Hello");
}, "json");
Get JSON using jQuery
JavaScript Object Notation (JSON) is a popular light weight format that can be used to get data from server. JSON has became very popular since that web pages have became interactive using AJAX. JSON format is easy to create from the server and easy to parse at client as it is the basic object representation in JavaScript.
JQuery provides a function that can be used to make an AJAX call and get the data in JSON format. Normally the data that we get from AJAX is converted in JSON by calling eval () method of JavaScript. But the function provided by JQuery handles this internally and provides direct JSON object as output.
jQuery.getJSON( url, [data], [callback] )
$.getJSON("http://api.flickr.com/services/feeds/photos_public.gne?tags=cat&tagmode=any&format=json&jsoncallback=?",
function(data){
$.each(data.items, function(i,item){
$("<img/>").attr("src", item.media.m).appendTo("#images");
if ( i == 3 ) return false;
});
});
AJAX Start/End using jQuery
While you make an AJAX call and get some data from server, it is good to show a progress bar or image to user so that (s)he knows that something is going on. Hence Loading… text is common in AJAX enabled application.
What if you web application is making many AJAX calls like gmail. You may want to display a Loading… text while any of AJAX call is proceeding. To achieve this ajaxStart() and ajaxComplete() methods of jQuery can be used.
ajaxStart() method registers a function handler that will be called by jQuery internally whenever an AJAX call is made. If already a request is active than the handler is not called. We can use this method to register a handler function that will display our progress bar.
$.ajaxStart(function() {
$("div#loading").text("Loading...");
});
In above code snippet, we used ajaxStart() method to register a function that set the innerHTML of div to Loading…
Similarly ajaxComplete() method can be used to register a handler function which gets called by jQuery when an AJAX request get completed and any other active request are not in progress.
$.ajaxComplete(function() {
$("div#loading").text("");
});
Serialize html form using jQuery
While submitting a form using AJAX, one has to create a input string that contains the value of all the input elements on the screen. It is very difficult to create this string if your form is very big. Hence we can use jQuery’s serialize() and serializeArray() method to do so.
serialize()
Serializes a set of input elements into a string of data. Serialize is typically used to prepare user input data to be posted to a server. The serialized data is in a standard format that is compatible with almost all server side programming languages and frameworks. In order to work properly serialize requires that form fields have a name attribute. Having only an id will not work.
var str = $("form").serialize();
$("#results").text(str);
In above code snippet, we created a serialize output of the form. This value can be sent to server by an AJAX call.
serializeArray()
serializeArray() does the similar job. Except it creates JSON output.
[
{name: 'firstname', value: 'Hello'},
{name: 'lastname', value: 'World'},
{name: 'alias'}, // this one was empty
]
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Excelent tutorial, direct, to the point, and in exactly the right order for developing an app!
Thanks
Comment:
Thank u for gooda tutorial. I got lot information about ajax using the jquery…
Keep on posting these types of good tuorials…….
Great work…..
All the best……
Good tutorial…
Hey,
It is a good help to me.
It might be useful to me.
You have collected the complete set, I like the way you’ve illustrated the methods,
and from now, I’ll use jQuery Ajax API
Thanks Dear… Grt tutorials… I hv been searching for json ajax requests for a long time… gud wrk
@Gaurav – Thanks for the good words.
hi, good tutorial. i would like to ask about ajaxStart and ajaxComplete methods. They are registered to every ajax call. How do we register each ajaxStart/ajaxComplete to each ajax call? suppose there are 2 section on screen that use ajax, each section requires Loading sign at specific position. or is there any technique to do this using jquery?
Thanks for your attention.
Very nice and useful tutorials for web designers,
Thanks for posting.
good yarrrrrrrrrrrr……….
Great tutorial. Most tutorials get into way to many unimportant details which leaves the reader confused. This is a great way to build a foundation for using jquery to perform Ajax since I’m a jquery newb. Thanks!
@Andy: Thanks for the comment. I appreciate that you liked the tutorial. Feel free to bookmark/share this article.
Great tutorial!
thanks its really important
its powerful tutorial for starting of Ajax with jQuery.
great tutorial.ur explanation is very nice and easy to understand for beginners also..
This could be a good read…
http://mahtonu.wordpress.com/2010/05/05/ajax-with-jquery-ajax-jquery-api/
Please help to fix my problem. I want to use load with post method. I am writting javascript function like below:
function test()
{
qString = “a:’1′,b:’2′,c:’3′
$(“#objectID”).load(“test.php”, {qString} );
}
the above function gives me error.
Instead of variable if i write function like below, then it works properly.
$(“#objectID”).load(“test.php”, {“a:’1′,b:’2′,c:’3′} );
Please let me know how I typecast qString.
Thank you.
Regards
Vikas Parab
HI Viral,
I want to merge two row having same value for whole table for perticular column. in Java script or JQ. we develoing intarnet application for my company.
Thanks this is just what we needed, excellent tutorial.
A really very informative tutorial on the subject.
Thank u for good tutorial…
Real decent jquery/ajax tut cheers
any working demo? thnx
hi, this is nice tutorial.
thanks
Thanks, this is just what I was looking for to start using AJAX. The only other think I’d have liked was a practical example of seeing all these working together, so that I could see what the ideal AJAX project should look like.
Thanks for the awesome tutorial. Spot on as usual. Just what i was looking for my project.
Thanks, good info. However passing “{key:value}” into the $.get method doesn’t work. You actually need to pass the values in as {key:value} without double quotes. E.g. {id: 1, name: “Bob”}
great tutorial….jquery is really my lovely library…thanks for sharing this.
nice tutorial
easy 2 understand,with easy words…thnks grt work
Thx for this very helpful tutorial..
It helped me in my project…:)
Very Helpful!
good ……
outstanding article
it really good article i am using your technique in our site
Looks nice. I will try it out to give you a feedback soon.
Easy to read, but a show about how the whole things work together under a simplified real setting would make it better.
thanks mate
Thank you so much for such a nice article.
i liked it very much.
Thank you for sharing. Mark
Bloody Awesome..
But I don’t prefer jQuery.post() or jQuery.get() method to do an ajax call as they don’t support error handling.
http://jquerybyexample.blogspot.com/2011/11/avoid-jquerypost-use-jqueryajax.html
I prefer jQuery.ajax() as it supports error handling as well.
how to get local server get json values simple example please help me.
example if local server path Get JSON url and data.
good tutorial but i use $.ajax() it is simple too…….
Very good tutorial….
It’s very needful….
Thanks
BEWARE: This technique won’t work except for getting json.
jquery documentation explains here (read “Additional Notes” at bottom) :
http://api.jquery.com/jQuery.get/
You can spend hours chasing errors if you don’t notice this detail!!!
So VP, please at least include the warning
nice 1..