尝试查看 PHP简单HTML DOM解析器

它具有与jQuery类似的出色语法，因此您可以轻松地通过ID或类选择所需的任何元素

It has brilliant syntax similar to jQuery so you can easily select any element you want by ID or class

// include/require the simple html dom parser file

$html_string = '
    <p class="Heading1-P">
        <span class="Heading1-H">Chapter 1</span>
    </p>
    <p class="Normal-P">
        <span class="Normal-H">This is chapter 1</span>
    </p>
    <p class="Heading1-P">
        <span class="Heading1-H">Chapter 2</span>
    </p>
    <p class="Normal-P">
        <span class="Normal-H">This is chapter 2</span>
    </p>
    <p class="Heading1-P">
        <span class="Heading1-H">Chapter 3</span>
    </p>
    <p class="Normal-P">
        <span class="Normal-H">This is chapter 3</span>
    </p>';
$html = str_get_html($html_string);
foreach($html->find('span') as $element) {
    if ($element->class === 'Heading1-H') {
        $heading[] = $element->innertext;
    }else if($element->class === 'Normal-H') {
        $content[] = $element->innertext;
    }
}