Display form validation error message on same page using only PHP?

Question

I'm very new to PHP and I've cobbled this together from some other answers on here. Can anyone show me how to get the $errMsg to display? At present, a blank or incorrect name leads to a blank page. Is this because the form isn't being displayed again? If so, how should I go about 'reloading' the form with the error message?

<?php
$name = "Fred";

if ($_SERVER["REQUEST_METHOD"] == "POST") {

  if (!empty($_POST["name"])) {

      if ($_POST["name"] == $name) {
        include("welcomeFred.php");
      }

      else {
        $errMsg = "Incorrect name";
      }

  }

  else {
    $errMsg = "Name required";
  }

}
else { ?>

  <html>
  ...
  <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
    <input type="text" name="name" required>
    <span><?php echo $errMsg;?></span>
    <input type="submit" value="Submit">
  </form>
  ...
  </html>

<?php } ?>

There is no need to put <?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?> in the action field of your form. If you leave this blank, the form will be sent to the current url. — Jerodev
– Jerodev, Commented Feb 13, 2017 at 13:39
@Jerodev But are there any security issues with the 'blank' approach? — Bricriu
– Bricriu, Commented Feb 13, 2017 at 13:50
Not that I can see, anyone could change that value using the html inspector, so if you leave it blank or not, the security will be the same. — Jerodev
– Jerodev, Commented Feb 13, 2017 at 13:51

Jerodev · Accepted Answer · 2017-02-13 13:40:27Z

1

You shouldn't put the rendering of the form in the else of your if structure. This is the reason your form isn't loaded when you submit the form.

Remove the else { ?> and <?php } ?> at the end of your file and it should work fine.

answered Feb 13, 2017 at 13:40

Jerodev

33.3k11 gold badges96 silver badges113 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Bricriu Over a year ago

Thank you - that makes a lot more sense, it's working now.

Jerodev Over a year ago

Glad I could help. Consider marking this answer as the solution if this helped you.

Collectives™ on Stack Overflow

Display form validation error message on same page using only PHP?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related