What is AJAX?
AJAX = Asynchronous JavaScript and XML. AJAX is a misleading name. You don't have to understand XML
to use AJAX. AJAX is a technique for creating fast and dynamic web pages. AJAX allows web pages to be updated asynchronously by
exchanging small amounts of data with the server behind the scenes. This means
that it is possible to update parts of a web page, without reloading the whole
page. Classic web pages, (which do not use AJAX) must reload the
entire page if the content should change. Examples of applications using AJAX: Google Maps, Gmail,
YouTube, and Facebook.
Why AJAX?
AJAX is use on based of following open standards:
- Browser-based
presentation using HTML and Cascading Style Sheets (CSS).
- Data is stored
in XML format and fetched from the server.
- Behind-the-scenes
data fetches using XMLHttpRequest objects in the browser.
- JavaScript to
make everything happen.
How to use AJAX?
Before you continue you should have a basic
understanding of the following:
Syntax
[selector].load( URL, [data], [callback] );
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URL − The URL of the server-side resource to
which the request is sent. It could be a CGI, ASP, JSP, or PHP script which
generates data dynamically or out of a database.
data − This optional parameter represents an
object whose properties are serialized into properly encoded parameters to be
passed to the request. If specified, the request is made using the POST method. If omitted, the GET method is used.
callback − A callback function invoked after the
response data has been loaded into the elements of the matched set. The first
parameter passed to this function is the response text received from the server
and second parameter is the status code.
Simple example of AJAX Call:
<html>
<head>
<title>The jQuery
Example</title>
<script type = "text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
//this is AJAX function to load the tag stored in result.html
<script type =
"text/javascript" language = "javascript">
$(document).ready(function() {
$("#driver").click(function(event){
$('#stage').load('jQuery/result.html');
});
});
</script>
</head>
<body>
<p>Click on the
button to load /jquery/result.html file</p>
<div id =
"stage" style = "background-color:cc0;">
STAGE
</div>
//this will create a button which will execute the function
<input type =
"button" id = "driver" value = "Load Data"
/>
</body>
</html>
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make another html file name it result.html and add this line to that and store it to the default dir and just change the path here $('#stage').load('jQuery/result.html'); in above code.
<h1>THIS IS RESULT...</h1>
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Other interesting things to know?
Query AJAX Methods
You have seen basic concept of AJAX using JQuery. Following
table lists down all important JQuery AJAX methods which you can use based your
programming need.
- jQuery.ajax( options ) Load a remote page using an HTTP request.
- jQuery.ajaxSetup( options ) Setup global settings for AJAX requests.
- jQuery.get( url, [data], [callback], [type] ) Load a remote page using an HTTP GET request.
- jQuery.getJSON( url, [data], [callback] ) Load JSON data using an HTTP GET request.
- jQuery.getScript( url, [callback] ) Loads and executes a JavaScript file using an HTTP GET request.
- jQuery.post( url, [data], [callback], [type] ) Load a remote page using an HTTP POST request.
- load( url, [data], [callback] )Load HTML from a remote file and inject it into the DOM.
