$re = '/<a(?:\s+name=".*?")?\s+href=.*?#.*?>(.*?)<\/a>/';
$str = '<a href="http://example.com/books/1">The Lord of the Rings</a>
<ul>
<li><a href="http://example.com/books/1#c1" >Chapter 1</a></li>
<li><a name="name before href" href="http://example.com/books/1#c2">Chapter 2</a></li>
<li><a href="http://example.com/books/1#c3" name="name after href">Chapter 3</a></li>
<li><a href="http://example.com/books/1#cN" target="_blank">Chapter N</a></li>
</ul>
<br><br>
<a href="http://example.com/books/1">Harry Potter</a>
<ul>
<li><a href="http://example.com/books/2#c1" target="_self">Chapter 1</a></li>
<li><a href="http://example.com/books/2#c2" name="some have name" title="some others have title" >Chapter 2</a></li>
<li><a href="http://example.com/books/2#c3">Chapter 3</a></li>
<li><a href="http://example.com/books/2#cN" >Chapter N</a></li>
</ul>';
preg_match_all($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