function tagsthanhvien($var){
$csdl=mysql_fetch_array(mysql_query("select * from users where name='{$var}'"));
if(mysql_num_rows(mysql_query("select * from users where name='{$var}'"))==0){
$nickname='@'.$var.'';
} else {
$nickname='<a href="../users/profile.php?user='.$csdl['id'].'">@'.$csdl['name'].'</a>';
}
return $nickname.' ';
}

public static function tags($var)
{
$var=$var.' ';

$var = preg_replace('#@(.*?)\s#se',"''.tagsthanhvien('$1').''",$var);
$var=trim($var);