How To solve dis synchronize of form Validation?

Question

I am wondering if anyone out there can help with my form Validation Please?

I am having a few problems trying to synchronized out how certain bits of the actual structure of the script works together.

<?php
$flag="OK";   // This is the flag and we set it to OK
$msg="";        // Initializing the message to hold the error messages
   if(isset($_POST['Send'])){
      $key=substr($_SESSION['key'],0,4);
      $num_key = $_POST['num_key'];
      if($key!=num_key){
      $msg=$msg."Your Key not valid! Please try again!<BR>";
      $flag="NOTOK";
           }
      else{
    $msg=$msg."Your Key is valid!<BR>";
    $flag="OK";
        } 
         }
$email=$_POST['email'];
echo "Your Email: ".$email." is";
if (!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $email)){
$msg=$msg."Invalid email<BR>";
$flag="NOTOK"; 
}else{
$msg=$msg."Valid Email<BR>";
$flag="OK";
}
$password=$_POST['password'];
if(strlen($password) < 5 ){ 
$msg=$msg."( Please enter password of more than 5 character length  )<BR>";
$flag="NOTOK"; 
}
if($flag <>"OK"){
echo "$msg <br> <input type='button' value='Retry' onClick='history.go(-1)'>";
}else{ // all entries are correct and let us proceed with the database checking etc …
} 
function spamcheck($field)
  {
  $field=filter_var($field, FILTER_SANITIZE_EMAIL);
  if(filter_var($field, FILTER_VALIDATE_EMAIL))
    {
    return TRUE;
    }
  else
    {
    return FALSE;
    }
  }
if (isset($_POST['email']))
  {//if "email" is filled out, proceed
  $mailcheck = spamcheck($_POST['email']); 
  if ($mailcheck==FALSE)
    {
    echo "Invalid input";
    }
      }
?>

the problem, when email valid, password valid, though key is invalid the warning of key disappear, it mean passed too... and also the spamcheck doesn't look work..

Answer 1

Each of you tests sets flag to "OK" or "NOTOK" overwriting decisions made by previous tests.
You could start with $flag = true;. And only if a test decides that the input is unsatisfying it sets $flag=false.
Or you can remove $flag altogether and check if 0===strlen($msg) after the tests.