Not displaying Error Message - php

Question

i am a newbie in this php. i am trying to make some validation for my form which will show the error msg if it exploits my validation rules.
my connection file.
<?php
$con = mysql_connect("localhost","root","") or die('could not connect the server: '. mysql_error());
mysql_select_db("interview",$con);
?>
my validate.php file
<?php
require_once('connect.php');
$realnameErr = $nickErr = $passwordErr = $emailErr = "";
$realname = $nick = $password = $email = "";
?>
my form
<form name='v2' id='login' method='post' action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<fieldset>
<legend>Login</legend>
<label for='realname' >Real Name*:</label>
<input type='text' name='realname' id='realname' maxlength="50" value="<?php echo $realname;?>" /></br>
<span class="error"><?php echo $realnameErr;?></span>
<br>
<label for='nick' >Nick*:</label>
<input type='text' name='nick' id='nick' maxlength="50" value="<?php echo $nick;?>" /></br>
<span class="error"><?php echo $nickErr;?></span>
<br>
<label for='password' >Password*:</label>
<input type='password' name='password' id='password' maxlength="50" /></br>
<span class="error"><?php echo $passwordErr;?></span>
<br>
<label for='email' >Email*:</label>
<input type='text' name='email' id='email' maxlength="50" value="<?php echo $email;?>"/></br>
</fieldset>
<input type='submit' name='submit' value='submit' />
</form>
validation begins here
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if(isset($_POST['submit'])) {
if (empty($_POST["realname"]))
{
$realnameErr = "Name is required";
}
else
{
$realname=test_input($_POST["realname"]);
if(!preg_match("/^[a-zA-z ]*$/",$realname))
{
$realnameErr = "only letters and white space allowed";
}}
if(empty($_POST["nick"]))
{
$nickErr = "Nick is required";
}
else {
$nick=($_POST["nick"]);
}
if(empty($_POST["password"]))
{
$passwordErr = "password is required";
}
else {
$password=($_POST["password"]);
}
if(empty($_POST["email"]))
{
$emailErr = "email is required";
}
else {
$email=test_input($_POST["email"]);
if(!preg_match("/([\w\-]+\#[\w\-]+\.[\w\-]+)/",$email))
{
$emailErr = "Invalid email format";
}}
checking then inserting
if((!$realnameErr) && (!$nickErr) && (!$passwordErr) && (!$emailErr)) {
$query="INSERT INTO `main`"."(realname,nick,password,email)". "VALUES". "('$realname','$nick',SHA('$password'),'$email')";
$res=mysql_query($query);
echo '<p>Your account has been Successfully created,You are now ready to login. </p>';
}
}}
function test_input($data)
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>

Answer 1

You need to have your working Script before you display your form. Because at the moment, the time you output <span class="error"><?php echo $nickErr;?></span> the variable $nickErr is still empty and therefore does not display anything.

Answer 2

Try this:
// Init
$errors = array();
// Validate Post Data
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (isset($_POST['submit'])) {
if (empty($_POST["realname"])) {
$errors[] = "Name is required";
} else {
$realname = test_input($_POST["realname"]);
if (!preg_match("/^[a-zA-z ]*$/", $realname)) {
$errors[] = "only letters and white space allowed";
}
}
if (empty($_POST["nick"])) {
$errors[] = "Nick is required";
} else {
$nick = ($_POST["nick"]);
}
if (empty($_POST["password"])) {
$errors[] = "password is required";
} else {
$password = ($_POST["password"]);
}
if (empty($_POST["email"])) {
$errors[] = "email is required";
} else {
$email = test_input($_POST["email"]);
if (!preg_match("/([\w\-]+\#[\w\-]+\.[\w\-]+)/", $email)) {
$errors[] = "Invalid email format";
}
}
}
}
// If there is any error
if (sizeof($errors))
{
// display it
echo '<div>Following error(s) occured:<br /><br />'. implode('<br />', $errors) .'</div>';
}
else
{
// proceed with db insert here
}