$re = '/<div class="article">(.*?)<\/div>/is';
$str = '<div class="article">
<p class="title">Test!</p>
<div>Content content</div>
<p>test test</p>
<div class="test">test</div>
<p>test</p>
</div>
<div class="article">
<p class="title">Test1!</p>
<div>Content content1</div>
<p>test test1</p>
<div class="test">test1</div>
<p>test1</p>
</div>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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