Question

So I have a form that looks so.

<form action="thanks.php" method="post" class="niceform" name="myform">
<table>
<tr>
<td><label for="company_name">Company Name</label></td>
<td><input type="text" name="company" value="" size="38" /></td>
</tr>
// and so on

I have the validation by javascript. But the problem is that when I go directly to thanks.php from localhost/mysite/form/thanks.php I have an empty row that is inserted when I look at phpmyadmin. Thanks.php looks like so.

<?php
// open the connection
$conn = mysql_connect("localhost", "root", "password");
// pick the database to use
mysql_select_db("company_register",$conn);

$sql = "INSERT INTO `tblsignups` VALUES ('NULL', '$_POST[company]', '$_POST[email]', '$_POST[phone]', '$_POST[address]', '$_POST[comments]', '$_POST[contact_person]')";

$result = mysql_query($sql, $conn) or die(mysql_error());

mysql_close($conn);
?>
// And I have a thank you msg I display

How do I check that if some one should directly go to thanks.php I tell them to go fill the form first and do not put anything on the database

Answer 1

here is a sketch example

after receiving POST data you have to check it and raise error flag
in case of some errors show the form back instead of saving it

<?  
if ($_SERVER['REQUEST_METHOD']=='POST') {  

  $err = array();
  //performing all validations and raising corresponding errors
  if (empty($_POST['name']) $err[] = "Username field is required";  
  if (empty($_POST['text']) $err[] = "Comments field is required";  

  if (!$err) {  
    // if no errors - saving data 
    // and then redirect:
    header("Location: ".$_SERVER['PHP_SELF']);
    exit;
  }  else {
    // all field values should be escaped according to HTML standard
    foreach ($_POST as $key => $val) {
      $form[$key] = htmlspecialchars($val);
    }
} else {
  $form['name'] = $form['comments'] = '';  
}
include 'form.tpl.php';
?>  

and modify your form to make it possible to show errors

<? if ($err): ?>
  <? foreach($err as $e): ?>
<div class="err"><?=$e?></div>
  <? endforeach ?>
<? endif ?>
<form>
  <input type="text" name="name" value="<?=$form['name']?>">
  <textarea name="comments"><?=$form['comments']?></textarea>
  <input type="submit">
</form>