include this library http://simplehtmldom.sourceforge.net/

include_once './htmldom/simple_html_dom.php';

$url = "your_url";

// Create a new HTML DOM object

$html = file_get_html($url);

// Find all H3 tags on the page

$h3Tags = $html->find('h3');

// Loop through each H3 tag and extract the text

foreach ($h3Tags as $h3) {

$h3Text = $h3->plaintext;

if (strtoupper($h3Text) == $h3Text) {

echo strtolower($h3Text);

}

}

// Clean up the HTML DOM object

$html->clear();