$re = '/<!--(.*?)-->|\s\B/m';
$str = '<body>
<!-- carousel slider section -->
<section id="carousel">
<div class="carouserl-item" id="carousel1">
<!-- gambar pertama -->
<img src="img1.jpg" alt="Image Description" width="300" height="600">
</div>
<div class="carouserl-item" id="carousel2">
<!-- gambar kedua -->
<img src="img2.jpg" alt="Image Description" width="300" height="600">
</div>
</section>
</body>';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php