$re = '/<[a-z]+ .*?(href|src|alt)="[^"]+"/';
$str = '<p>paragraph<a>link</a></p>
<div class="myclass">
<div>something</div>
<div style="mystyle">something</div>
<b><a href="#">link</a></b>
<b><a href="#" name="a name">link</a></b>
<b style="color:red">bold</b>
<img src="../path" alt="something" />
<img src="../path" alt="something" class="myclass" />
</div>\'';
preg_match_all($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