$re = '/>\s+</';
$str = '<div>
<p>Some paragraph here</p>
<div data="some data > < here">
<p>some subparagraph here</p>
</div>
</div>';
$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