Form fields that MUST be filled in

[popcop]

Ive created a form in PHP which sends an automatic email to me.

I want the the form to fuction so that the email address field MUST be filled in.

how is this achieved?

thanks in advance

[jonra]

I use both Javascript on the client side to validate if it's an email address, and PHP on the backend to check if it's valid. You'll basically be able to search for the @ and . with the strings in between.

[popcop]

would you be able to help me out with this?

this is all new to me

[jonra]

I don't have any code off hand, but it's not bad. Just grab the form field by ID in Javascript, put it into a variable, and run a check on what is actually in the variable. If there's 'something'@'something'.'something' return true, else return false. Maybe someone else has some code for you.

[popcop]

Anyone Have This Code Handy?

[NogDog]

// assume form field name is "email":
$email = trim($_POST['email']); // get rid of leading/trailing whitespace
if(empty($email))
{
  // handle error here (display error message, or return to form via header(), etc.)
}
else
{
  // proceed with form processing
} 

[Oly701]

EDIT: Hrm, this is actually way overkill for what you want. If you just want to verify the field is not empty, then NogDog nailed it for you.

Error checking e-mail is not fun. This is by no means perfect, but its a start (should be used after you've checked to make sure the field is not empty).

   // Check syntax
   $validEmailExpr =  "^[0-9a-z~!#$%&_-]([.]?[0-9a-z~!#$%&_-])*" .
                      "@[0-9a-z~!#$%&_-]([.]?[0-9a-z~!#$%&_-])*$";

   if (!eregi($validEmailExpr, $_SESSION["{$formVars}"]["{$field}"]))
   {
      $_SESSION["{$errors}"]["{$field}"] =  
         "The email must be in the name@domain format.";
      return false;
   } 

I did not write this originally, just a snippet I'd stored at some point. Another option would be to verify the the e-mail domain exists by checking the MX record or just doing a hostname lookup.

[NogDog]

Here's the email format validation function I use:

# email address validation function
# kudos to http://iamcal.com/publish/articles/php/parsing_email/pdf/
function is_valid_email_address($email) {
  $qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]';
  $dtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]';
  $atom = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c'.
  '\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+';
  $quoted_pair = '\\x5c\\x00-\\x7f';
  $domain_literal = "\\x5b($dtext|$quoted_pair)*\\x5d";
  $quoted_string = "\\x22($qtext|$quoted_pair)*\\x22";
  $domain_ref = $atom;
  $sub_domain = "($domain_ref|$domain_literal)";
  $word = "($atom|$quoted_string)";
  $domain = "$sub_domain(\\x2e$sub_domain)*";
  $local_part = "$word(\\x2e$word)*";
  $addr_spec = "$local_part\\x40$domain";
  return preg_match("!^$addr_spec$!", $email) ? 1 : 0;
} 

This is a very complete interpretation of the RFC822 email address specification, and should give no false positives or false negatives (as far as format goes, not whether the address actually exists).

[Oly701]

Ah, very nice NogDog.

/me copies for later use

Thanks!

[The Little Guy]

If you still need help with empty feilds, than Here is a code I made: http://php.d-top.org/index.php?page=empty_feilds

at the very bottom, their is this line: mysql_query("INSERT INTO id(`first`, `last`) VALUES ('$first', '$last')") or die(mysql_error());

With that line, you would switch that out with you email code, as posted above.