Implementation code for parsing html with php

Recently I want to use PHP to write a crawler, which requires parsing HTML. I found a project called PHP Simple HTML DOM Parser on sourceforge. It can return specified DOM elements through a CSS selector in a jQuery-like way. It is very powerful.
First introduce the file simple_html_dom.php at the beginning of the program
Copy the code The code is as follows:
include_once('simple_html_dom.php');

PHP Simple HTML DOM Parser provides 3 ways to create DOM objects
The code is as follows:
// Create a DOM object from a string
$html = str_get_html('Hello!');
// Create a DOM object from a URL
$html = file_get_html('http://www.google.com/');
// Create a DOM object from a HTML file
$html = file_get_html('test.htm');

After getting the DOM object Various operations can be performed
Copy code The code is as follows:
// Find all anchors, returns an array of element objects
$ret = $html->find('a');
// Find (N)th anchor , returns element object or null if not found (zero based)
$ret = $html->find('a', 0);
// Find lastest anchor, returns element object or null if not found (zero based)
$ret = $html->find('a', -1);
// Find all