How To Get All Links From Page Content

$site_url = "http://scriptforphp.blogspot.com"
$string = file_get_contents($site_url);

preg_match_all("|\<a\ href=\"(.*)\"|U",$string, $results); // Get Only URL
preg_match_all("|\<a\ (.*)\<\/a\>|U",$string, $results); // Get Whole Link

$url = $results[1];

foreach($urls as $url)
{
echo htmlentities($url).'<br />';
}