PHP Example – AJAX and XML Complete Tutorial

Before JSON became popular, XML was the most commonly used format for AJAX responses. Even today, XML is still used in many legacy systems, APIs, and enterprise applications.

This tutorial explains how to use AJAX with XML in PHP, showing how PHP generates XML data and how AJAX reads and displays it without reloading the page.

What Is AJAX and XML in PHP?

AJAX sends asynchronous requests from the browser
XML is a structured data format
PHP generates or processes XML on the server

AJAX + XML allows the browser to fetch structured data from PHP and update part of a webpage dynamically.

Why Use XML with AJAX in PHP?

Using XML is useful when:

Working with legacy systems
Integrating SOAP-based APIs
Handling structured hierarchical data
Learning core AJAX concepts

How AJAX Works with XML in PHP

Flow:

JavaScript sends AJAX request
PHP processes request
PHP generates XML response
JavaScript reads XML
Webpage updates content

Prerequisites for AJAX XML Tutorial

Before starting, you should know:

Basic HTML
Basic JavaScript
PHP fundamentals
How PHP runs on a server

Example Scenario for AJAX and XML

We will:

Request user data using AJAX
PHP will return data in XML format
JavaScript will parse XML and display it

Step 1: XML Data Generated by PHP

Create a PHP file named data.php

<?php
header("Content-Type: text/xml");

echo '<?xml version="1.0" encoding="UTF-8"?>';
echo "<users>";

echo "<user>";
echo "<name>Rahul</name>";
echo "<email>rahul@gmail.com</email>";
echo "</user>";

echo "<user>";
echo "<name>Amit</name>";
echo "<email>amit@gmail.com</email>";
echo "</user>";

echo "</users>";
?>

Step 2: HTML and AJAX JavaScript Code

Create index.html

<!DOCTYPE html>
<html>
<head>
    <title>AJAX XML Example</title>
    <script>
        function loadXML() {
            var xhr = new XMLHttpRequest();
            xhr.open("GET", "data.php", true);

            xhr.onreadystatechange = function () {
                if (xhr.readyState == 4 && xhr.status == 200) {
                    var xml = xhr.responseXML;
                    var users = xml.getElementsByTagName("user");
                    var output = "";

                    for (var i = 0; i < users.length; i++) {
                        var name = users[i].getElementsByTagName("name")[0].childNodes[0].nodeValue;
                        var email = users[i].getElementsByTagName("email")[0].childNodes[0].nodeValue;

                        output += name + " - " + email + "<br>";
                    }

                    document.getElementById("result").innerHTML = output;
                }
            };

            xhr.send();
        }
    </script>
</head>
<body>

<button onclick="loadXML()">Load XML Data</button>
<div id="result"></div>

</body>
</html>

Output on Button Click

Rahul - rahul@gmail.com
Amit - amit@gmail.com

The page loads XML data without refreshing.

Example: AJAX XML with PHP and MySQL

PHP can also generate XML from a database.

<?php
header("Content-Type: text/xml");
include "db.php";

echo "<?xml version='1.0' encoding='UTF-8'?>";
echo "<users>";

$result = mysqli_query($conn, "SELECT * FROM users");

while ($row = mysqli_fetch_assoc($result)) {
    echo "<user>";
    echo "<name>".$row['name']."</name>";
    echo "<email>".$row['email']."</email>";
    echo "</user>";
}

echo "</users>";
?>

Difference Between XML and JSON in AJAX

Feature	XML	JSON
Readability	Verbose	Lightweight
Parsing	Slower	Faster
Popularity	Declining	Very high
Structure	Tag-based	Key-value

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Common Mistakes When Using AJAX XML

Forgetting Content-Type header
Incorrect XML structure
Not using responseXML
Parsing text instead of XML

Best Practices for AJAX and XML in PHP

Always set correct headers
Validate XML structure
Escape special characters
Use XML only when required
Prefer JSON for modern apps

Frequently Asked Questions (FAQ)

1. Is XML still used with AJAX?

Yes, mainly in legacy and enterprise systems.

2. Which is better, XML or JSON?

JSON is better for modern applications.

3. Can PHP generate XML?

Yes, easily using echo or DOM functions.

4. How does JavaScript read XML?

Using responseXML property.

5. Does XML work without database?

Yes, XML can be static or dynamic.

PHP Example – AJAX and XML Tutorial