$re = '/(classId=|id=)([^&]*)/';
$str = '<a href="http://172.23.4.16/Workplace/Browse.jsp?eventTarget=WcmController&eventName=GetInfo&id={350B278C-DE7D-44DE-9B54-099672152476}&vsId=&classId={F14AC85A-4474-479A-9B4E-BCBA180B7975}&objectStoreName=Nice&majorVersion=&minorVersion=&versionStatus=&mimeType=&mode=&objectType=customobject&isPopup=true" target="_blank">';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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