How to use php to grab the email address code in the web page

 /**
 desc: code to collect the email in the webpage
*/
 $url='http://www.xxx.net'; //The URL to be collected
 $content=file_get_contents($url);
 //echo $content;
 function getEmail($str) {
 //$pattern = "/([a-z0-9]*[-_.]?[a-z0-9]+)*@([ a-z0-9]*[-_]?[a-z0-9]+)+[.][a-z]{2,3}([.][a-z]{2})?/i";
 $pattern = "/([a-z0-9-_.]+@[a-z0-9]+.[a-z0-9-_.]+)/";
 preg_match_all($pattern,$str ,$emailArr);

 return $emailArr[0];
 }
 print_r( getEmail($content));
 ?>

How to use, email address, php