How can the use of comments in HTML code affect the matching of regular expressions in PHP?

When using regular expressions in PHP to parse HTML code, the presence of comments can interfere with the pattern matching. To avoid this issue, you can use the `s` modifier in your regular expression pattern to treat the input as a single line, ignoring line breaks. This will allow the regular expression to match across lines, including comments. 

$html = '<!-- This is a comment -->
<div class="content">
    <p>Hello, world!</p>
</div>';

$pattern = '/<div class="content">(.*?)<\/div>/s';
preg_match($pattern, $html, $matches);

echo $matches[0]; // Output: <div class="content"><p>Hello, world!</p></div>

Keywords

HTML comments regular expressions matching PHP

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