$re = '~<(a|h1)\b.*?</\1>(*SKIP)(*F)|(222)~si';
$str = '<p>111 222 333</p>
<li>111 222 333</li>
<h1>111 222 333</h1>
<h2>111 222 333</h2>
<strong>111 222 333</strong>
<p><strong>111 222 333</strong></p>
<p>111 <a href="">222</a> 333</p>';
$subst = "<a href=\"#link\">\2</a>";
$result = preg_replace($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