<?php 
function is_email($mail)
                {
                  if(strpos($mail, '@') === false) return false;
                  $host = explode("@",$mail); $mxarr = array();
                  $regexp = '/^[-!#$%&\'*+\\.\/0-9=?A-Z^_`{|}~]+@([-0-9A-Z]+\.)+([0-9A-Z]){2,4}$/i';
                  if (!preg_match($regexp, $mail)) return false;
                  if (function_exists('getmxrr') && !getmxrr($host[1],$mxarr)) return false;
                  
                  return true;
                }
                if(isset($_POST['email']))
                {
                    if(is_email($_POST['email']))
                    {
                        $dataReader=$command->query("INSERT INTO email_tbl (email) VALUES (".$_POST['email'].");");

                    }
                } 1