---
title: dataValidate (en)
description: A set of PHP form validation functions that use ereg() regular expressions to check fields, email, HKID, phone number, and birth date.
url: "https://aaronchan.com/kb/data-validate/"
updated: "2026-09-15"
category: "Code-php+MySQL (en)"
---

# dataValidate (en)

A set of PHP form validation functions that use `ereg()` regular expressions to check that fields are filled in, an email address looks valid, and the basic format of a Hong Kong ID (HKID), phone number, and birth date. Run it before processing user input.

 Copy

```
<?

function filled_out($form_vars)
{
  // test that each variable has a value
  foreach ($form_vars as $key => $value)
  {
     if (!isset($key) || ($value == ""))
 // test suspended!!!!
        return true;
  }
  return true;
}

function valid_email($address)
{
  // check an email address is possibly valid
  if (ereg("^[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$", $address))
    return true;
  else
    return false;
}

function valid_hkid($hkid_int, $hkid, $hkid_cd)
{
 // check an HKID is possily valid
  if ((ereg("[a-zA-Z]{1}", $hkid_int)) && (ereg("[0-9]{6}", $hkid)) && (ereg("[a-zA-Z0-9]{1}", $hkid_cd)))
  	return true;
  else
   return false;
 }

function valid_phone($phone)
{
 // check an HKID is valid
  if (ereg("[0-9]", $phone))
  	return true;
  else
   return false;
 }

function valid_bday($bday)
{
 // check an HKID is valid
  if (($bday < date("Y")-100) || ($bday > date("Y")-12))
  	return false;
  else
   return true;
 }

?>
```

**Note:** `ereg()` was deprecated in PHP 5.3 and removed in PHP 7 — new projects should use `preg_match()` instead.