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COMPUTER SOFTWARE APPLICATION - CITS
<body>
<div id=”demo”>
<h2>Let AJAX change this text</h2>
<button type=”button” onclick=”loadDoc()”>Change Content</button>
</div>
</body>
</html>
The HTML page contains a <div> section and a <button>.
The <div> section is used to display information from a server.
The <button> calls a function (if it is clicked).
The function requests data from a web server and displays it:
Function loadDoc()
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById(“demo”).innerHTML = this.responseText;
}
};
xhttp.open(“GET”, “ajax_info.txt”, true);
xhttp.send();
}
What is AJAX?
AJAX is an acronym for Asynchronous JavaScript and XML. It is a group of inter-related technologies like
JavaScript, DOM, XML, HTML/XHTML, CSS, XMLHttpRequest etc.
AJAX allows you to send and receive data asynchronously without reloading the web page. So it is fast.
AJAX allows you to send only important information to the server not the entire page. So only valuable data from
the client side is routed to the server side. It makes your application interactive and faster.
AJAX = Asynchronous JavaScript And XML.
AJAX is not a programming language.
AJAX just uses a combination of:
• A browser built-in XMLHttpRequest object (to request data from a web server)
• JavaScript and HTML DOM (to display or use the data)
AJAX is a misleading name. AJAX applications might use XML to transport data, but it is equally common to
transport data as plain text or JSON text.
AJAX allows web pages to be updated asynchronously by exchanging data with a web server behind the scenes.
This means that it is possible to update parts of a web page, without reloading the whole page.
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CITS : IT&ITES - Computer Software Application - Lesson 37 - 46
