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AJAX Tutorial


AJAX

AJAX is a developer's dream, because you can:

Update a web page without reloading the page
Request data from a server - after the page has loaded
Receive data from a server - after the page has loaded
Send data to a server - in the background


Try it Yourself Examples in Every Chapter

In every chapter, you can edit the examples online, and click on a button to view the result.

AJAX Example

Let AJAX change this text

Try it Yourself »


AJAX Example Explained

HTML Page

<!DOCTYPE html>
<html>
<body>

<div id="demo"><h2>Let AJAX change this text</h2></div>

<button type="button" onclick="loadDoc()">Change Content</button>

</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 (xhttp.readyState == 4 && xhttp.status == 200) {
     document.getElementById("demo").innerHTML = xhttp.responseText;
    }
  };
  xhttp.open("GET", "ajax_info.txt", true);
  xhttp.send();
}

Start learning AJAX now!