Complete Guide to Parsing and Processing HTML/XML Documents with DOM in PHP

M66 2025-07-30

Complete Guide to Parsing and Processing HTML/XML Documents with DOM in PHP

In web development, parsing and processing HTML or XML documents is a common task. PHP provides the DOM (Document Object Model) technology to help developers efficiently manipulate and process these documents. DOM is a platform-independent API that represents and manipulates documents in a tree-like structure, supporting operations such as add, delete, modify, and query nodes.

In this tutorial, we will demonstrate how to use PHP to parse and process HTML/XML documents using DOM by extracting data such as titles and links.

DOM Parsing Example

Let’s assume we have the following HTML document, which contains some basic tags and content:

<!DOCTYPE html>
<html>
  <head>
    <title>Sample Document</title>
  </head>
  <body>
    <h1>Welcome to the DOM Parsing Example</h1>
    <ul>
      <li><a href="https://www.example.com">Sample Link 1</a></li>
      <li><a href="https://www.example.com">Sample Link 2</a></li>
      <li><a href="https://www.example.com">Sample Link 3</a></li>
    </ul>
  </body>
</html>

Our goal is to parse this HTML document using PHP and extract the title and all the links.

PHP Code Example

Below is the PHP code that uses the DOM object to parse the above HTML document:

<?php
// Create a DOM object
$dom = new DOMDocument();

// Load the HTML document
$dom->loadHTMLFile('example.html');

// Get all h1 tags
$headings = $dom->getElementsByTagName('h1');
foreach ($headings as $heading) {
    echo 'Title: ' . $heading->nodeValue . '<br>';
}

// Get all a tags
$links = $dom->getElementsByTagName('a');
foreach ($links as $link) {
    echo 'Link: ' . $link->getAttribute('href') . '<br>';
}
?>

Code Output

The output when running the code would be:

Title: Welcome to the DOM Parsing Example
Link: https://www.example.com
Link: https://www.example.com
Link: https://www.example.com

As you can see, by using the related DOM methods, we successfully parsed the HTML document and extracted the title and all the links.

Conclusion

PHP’s DOM extension provides an easy way to parse and process HTML/XML documents. It allows for node traversal, querying, attribute retrieval, node deletion, and insertion. Its platform independence makes it suitable for various development environments.

In real-world applications, DOM can be combined with other technologies such as XPath to handle more complex HTML/XML structures. We hope this tutorial helps you master how to parse documents using DOM in PHP and apply it flexibly in your projects.

This tutorial only covers the basics of DOM parsing. In practice, the HTML/XML structures you encounter may be more complex, and developers can extend and optimize their use of DOM as needed.

Related Tags:
HTML