2 replies to this topic

[John Ugwuozor]

How can I validate a form with PHP

Edited by Roger, 05 August 2010 - 02:59 PM.

[Orjan]

Mainly, you check each value in the form and returns error messages and shows the form again if the validation failed. How you do it is so different to each form of validation
but an example could be:

if ($_POST['submit'] != "") {

// this is where we do the validation.

  if ($_POST['myfield'] == "") {

     $errormessage = "you need to write something";

  } else if (strlen($_POST['myfield'] > 30) {

    $errormessage = "Please don't write more than 30 characters";

}

if ($errormessage != "" || $_POST['submit'] == "") {

// if there is an error, or, the form isn't submitted yet, print the form

   echo '<form method="POST" action="form.php">';

   echo '<input type="text" name="myfield" value="'.$_POST['myfield'].'" />';

   echo '<input type="submit" name="submit" value="Send in form" />';

   echo $errormessage;

} else {

// what to do if the validation passed

   echo "you wrote ". $_POST['myfield'];

}