Resolved System keep updating table even registration fail

[Jian0203]

Case 1: Empty fields -> update into database too(wrong!).
Case 2: Register email is not valid -> update into database too(wrong!).
Case 3: Username already exist -> update into database too(wrong!).

the system shouldn't update the database if the cases above happen but it does update nor matter how.

can anyone please check for me ? Thank you so much and i appreciate that a lots ^^

Part of register.php

PHP Code:

<?php

if (isset ($_POST['register_username'], $_POST['register_email'])){

    $password1=0;
    $password2=0;
    $password3=0;
    $password4=0;
    $password5=0;
    
    $register_username = $_POST["register_username"];    
    $register_email = $_POST["register_email"];    
    $password1 = $_POST["pass1"];
    $password2 = $_POST["pass2"];
    $password3 = $_POST["pass3"];
    $password4 = $_POST["pass4"];
    $password5 = $_POST["pass5"];
    
    $errors = array();
    
    if (empty($register_username) || empty($register_email) || empty($password1) || empty($password2) || empty($password3) || empty($password4) || empty($password5)){
        $error[] = '';
?>

<script type = "text/javascript">

    alert("Please fill in all fields.");
    
</script>

<?php        
    }else{
    
    if (filter_var($register_email, FILTER_VALIDATE_EMAIL) === false) {
        $error[] = '';
?>
    
<script type = "text/javascript">

    alert("Email address not valid.");
    
</script>

<?php
    
    }
    
    if (strlen($register_username) > 30 || strlen($register_email >255)){
        $error[] = '';
?>

<script type = "text/javascript">

    alert("One or more fields contain too many characters.");
    
</script>

<?php
    
    }
    
    if (user_exists($register_username) === true){
        $error[] = '';
        
    }
    
  }
  
  if (!empty($errors)) {
    foreach ($errors as $error) {
    
?>

<script type = "text/javascript">

    alert("Registration error. Please try again.");
    
</script>

<?php 

    } 
    } else {

    $register = user_register($register_username, $password1, $password2, $password3, $password4, $password5, $register_email); 
    $_SESSION['customer_email'] = $register;
?>

<script type = "text/javascript">

        alert("Your have successfully registered!");
        location = "welcome.php";
        
</script>

<?php
    exit();
    }
    
}
?>

Part of user.func.php

PHP Code:

function user_register($customer_username, $customer_pass1, $customer_pass2, $customer_pass3, $customer_pass4, $customer_pass5, $customer_email){

    $customer_username = mysql_real_escape_string($customer_username);
    $customer_pass1 = mysql_real_escape_string($customer_pass1);
    $customer_pass2 = mysql_real_escape_string($customer_pass2);
    $customer_pass3 = mysql_real_escape_string($customer_pass3);
    $customer_pass4 = mysql_real_escape_string($customer_pass4);
    $customer_pass5 = mysql_real_escape_string($customer_pass5);
    $customer_email = mysql_real_escape_string($customer_email);
    mysql_query("INSERT INTO `customerdetail` VALUES ('$customer_username', '$customer_pass1', '$customer_pass2', '$customer_pass3', '$customer_pass4', '$customer_pass5', '$customer_email')");
}

function user_exists($customer_username){

    $customer_username = mysql_real_escape_string($customer_username);
    $query = mysql_query ("SELECT COUNT(customer_email) FROM `customerdetail` WHERE `customer_username` = '$customer_username'");
    return (mysql_result($query, 0) == 1) ? true : false;
} 


[AndrewGSW]

PHP Code:

strlen($register_email >255) // should be
strlen($register_email) >255 


and

PHP Code:

if (!empty($errors)) { 


you are setting $error(s)[] = '' which is still considered to be empty.

empty(): Returns FALSE if var exists and has a non-empty, non-zero value. Otherwise returns TRUE.

The following things are considered to be empty:

"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
$var; (a variable declared, but without a value)

Actually, you have two arrays: errors and error; I assume there should only be one(?).