The function below valid_email takes in the email address to be validated.  In the example below "The email address is invalid." will be displayed on the screen.

<?

function valid_email($address)
 {
       // check an email address is possibly valid
       if (eregi("^[_a-z0-9-]+(\\.[_a-z0-9-]+)*@[a-z0-9-]+(\\.[a-z0-9-]+)*(\\.[a-z]{2,3})$", $address)){
            return true;
       } else { 
            return false;
       }
 }

$testemailaddress = "abchere.com";

if(valid_email($testemailaddress )){

      echo "The email address is valid.";

} else {

      echo "The email address is invalid";

}

?>