Example of parsing and processing HTML/XML using DOM in PHP
Examples of using DOM to parse and process HTML/XML in PHP
Introduction:
In web development, it is often necessary to parse HTML or XML documents and processing to obtain the data therein or to modify the document. PHP provides a variety of ways to implement this function, one of the commonly used ways is to use DOM (Document Object Model).
DOM is a standard, platform-independent API for representing and processing XML and HTML documents in a tree structure. It allows developers to access and manipulate various parts of a document in a language-independent manner. By using DOM, we can add, delete, modify and check documents to meet our needs.
Below we use a simple example to demonstrate how to use DOM to parse and process HTML/XML documents in PHP.
Example:
We assume there is a simple HTML document containing some simple tags and content. Our goal is to parse this document using the DOM via PHP and extract the titles and links within it.
The following is the content of a sample HTML document:
<!DOCTYPE html>
<html>
<head>
<title>示例文档</title>
</head>
<body>
<h1 id="欢迎使用DOM解析示例">欢迎使用DOM解析示例</h1>
<ul>
<li><a href="https://www.example.com">示例链接1</a></li>
<li><a href="https://www.example.com">示例链接2</a></li>
<li><a href="https://www.example.com">示例链接3</a></li>
</ul>
</body>
</html>We use PHP to parse the document and extract the titles and links. The code is as follows:
<?php
// 创建一个DOM对象
$dom = new DOMDocument();
// 加载HTML文档
$dom->loadHTMLFile('example.html');
// 获取所有的h1标签
$headings = $dom->getElementsByTagName('h1');
foreach ($headings as $heading) {
echo '标题: '. $heading->nodeValue . '<br>';
}
// 获取所有的a标签
$links = $dom->getElementsByTagName('a');
foreach ($links as $link) {
echo '链接: '. $link->getAttribute('href') . '<br>';
}
?>Parsing results:
Running the above code will output the following results:
标题: 欢迎使用DOM解析示例 链接: https://www.example.com 链接: https://www.example.com 链接: https://www.example.com
We can see that by using the relevant methods of DOM, we successfully parsed HTML document, and extracted the title and link information.
Conclusion:
Using DOM to parse and process HTML/XML documents in PHP is a common and powerful way. DOM provides a rich API to process documents. We can easily perform node traversal and query, attribute acquisition and setting, node deletion and insertion, etc. At the same time, the language independence of DOM allows developers to use it flexibly in various environments.
The above examples simply demonstrate the basic usage of DOM, and the actual situation may be more complicated. In practical applications, we can also combine XPath and other technologies to further optimize the use of DOM to meet more complex needs.
I hope that through the introduction of this article, readers can understand the basic methods of using DOM to parse and process HTML/XML in PHP, and can use it flexibly in actual development.
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