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PHP

Matthew Lang
Matthew Lang
13,483 Points
Posted by Matthew Lang
Matthew Lang
13,483 Points

Form Validation doesn't work PHP

Hey. Trying to do some form validation on my own, but I have stumbled into a problem. I am using the POST method, and the action is just PHP_SELF. As I display the form, below each field I am using PHP to check an 'error' array, and if it has items, display the strings. Once the user submits the form, it then goes through a validation check. Currently I only have 1 validation check, and that is for the username to not contain any whitespace. If it does contain whitespace, then it adds a string onto the username_err array, which should then be displayed back to the user, right? well, it doesn't and I'm stuck. any help? Here's my code

<div class="sign-up-form">
  <h1>Register an account</h1>
  <p>Already have an account? <a id="login-refer" href='login.php'>Log in.</a></p>
  <form method="POST" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
    <?php
      // Initialize variables for error reporting
      $username_err = [];
      $password_err = [];
    ?>

    <!-- Username -->
    <label for='label_username'>Username</label><br>
    <input type='text' id='label_username' name="input-username"></input><br>
    <?php
      if(count($username_err) > 0) {
        foreach($username_err as $error) {
          echo '<p class="error">' . $error . '</p>';
        }
      }
    ?>
    <!-- Email -->
    <label for='label_email'>Email</label><br>
    <input type='email' id='label_email' name="input-email"></input><br>
    <!-- Password -->
    <label for='label_password'>Password</label><br>
    <input type='password' id='label_password' name="input-pass"></input><br>
    <!-- Re-Type Password -->
    <label for='label_repassword'>Re-type Password</label><br>
    <input type='password' id='label_repassword' name="input-repass"></input><br>
    <?php
      if(count($password_err) > 0) {
        foreach($password_err as $error) {
          echo '<p class="error">' . $error . '</p>';
        }
      }
    ?>
    <!-- Submit -->
    <input type='submit' value='Register'></input>

    <?php
      // Validation of form checking
      if(isset($_POST['input-username'])) {
        $username = $_POST['input-username'];
        $email = $_POST['input-email'];
        $password = $_POST['input-pass'];
        $repassword = $_POST['input-repass'];
      }

      if(trim($username) !== $username) {
        $username_err[] = "Username must not contain any spaces.";
      }
    ?>
  </form>
</div>
Ben Payne
Ben Payne
1,464 Points

Hey Mathew,

You're overwriting the error arrays right after the opening form tag. So whatever was in there from the validation is gone. Also, inputs are self closing, they don't need a </input> closing tag.

I reworked the script for you here:

<?php

// Initialize variables for error reporting
$username_err = [];
$password_err = [];

// Validation of form checking
if (isset($_POST['input-username'])) {
    $username = $_POST['input-username'];
    $email = $_POST['input-email'];
    $password = $_POST['input-pass'];
    $repassword = $_POST['input-repass'];
}

if (trim($username) !== $username) {
    $username_err[] = "Username must not contain any spaces.";
}

?>
<div class="sign-up-form">
    <h1>Register an account</h1>
    <p>Already have an account? <a id="login-refer" href='login.php'>Log in.</a></p>
    <form method="POST" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>">
        <input type="hidden" name="_token" value="<?= $_SESSION['token'] ?>">

        <!-- Username -->
        <label for='label_username'>Username</label><br>
        <input type='text' id='label_username' name="input-username">

        <?php if (count($username_err) > 0) : ?>
            <?php foreach ($username_err as $error) : ?>
                <p class="error"><?= $error ?></p>
            <?php endforeach; ?>
        <?php endif ?>

        <!-- Email -->
        <label for='label_email'>Email</label><br>
        <input type='email' id='label_email' name="input-email"><br>

        <!-- Password -->
        <label for='label_password'>Password</label><br>
        <input type='password' id='label_password' name="input-pass"><br>

        <!-- Re-Type Password -->
        <label for='label_repassword'>Re-type Password</label><br>
        <input type='password' id='label_repassword' name="input-repass"><br>

        <?php if (count($password_err) > 0) : ?>
            <?php foreach ($password_err as $error) : ?>
                <p class="error"><?= $error ?></p>;
            <?php endforeach ?>
        <?php endif ?>

        <!-- Submit -->
        <input type='submit' value='Register'>
    </form>
</div>
  • Ben
Matthew Lang
Matthew Lang
13,483 Points
Matthew Lang
Matthew Lang
13,483 Points

Thank you so much! Now that you've pointed it out to me it makes so much sense now and I feel really dumb. thank you :)