我目前有一个 web 表单，用 html 编程，我有一个 php 内容处理程序，它检查错误，并完成所有需要做的事情，但如果有错误，我很想在 web 表单页面本身上显示错误，我不知道如何做到这一点，但我可以发送我的代码。
在这个问题上的任何帮助都会很有用，谢谢。
HTML 文档
Do you like the content on our website? Do you want to be a part of it? Want to earn more Karma?<br />
Do you have what it takes to be a content creator? Then sign up here!<br> <br>
<?php
function getUID()
{
global $user;
if ($user->uid)
{
$userID=$user->uid;
echo $userID;
}
else
{
header('Location: http://brokendiamond.org/?q=node/40');
}
}
function getUN()
{
global $user;
if ($user->uid)
{
$username=$user->name;
}
echo $username;
}
?>
<form name="input" action="php-scripts/sendmail.php" method="post">
Username:  
<input type="hidden" name="UserID" value="<?php getUID() ?>">
<input type="text" name="username" value="<?php getUN() ?>" /><br>
E-mail adress:
<input type="text" name="mail" /><br><br>
What type of 'Content Creator' do you want to become? <br />
<input type="radio" name="CCT" value="Blogger" /> Blogger<br />
<input type="radio" name="CCT" value="Livestreamer" /> Livestreamer<br> <br>
What's your motivation?<br />
<textarea name="motivation" cols="60" rows="6"></textarea><br><br>
Why should we pick you as content creator?<br />
<textarea name="whyshouldwe" cols="60" rows="6"></textarea><br><br>
Do you have some reference material?<br />
<textarea name="reference" cols="60" rows="6"></textarea><br><br>
<h3>Rules to content creation</h3>
<p>You can only submit this once every day, the other versions will not be read, and you will lose Karma for each submit.<br />
When u submit this form, we will examine your account, and we will take a close look to your reference material.<br>
<h4>For Livestreamers Only</h4>
If we think you have what it takes to be a livestreamer ( frequent hours required ) we will examine your stream, and your computer/internet potential.<br />
If that is good enough for the website, you'll become a content creator.<br>
<h4>For Bloggers</h4>
If we think you are blogging material for out website, you will become a content creator, once you are accepted onto the team we will track your progress.<br />
If however you neglect your power or publish inappropriate content, then we will have no choice but to remove you from our team and will revert you to a regular user account.<br><br>
<input name="Send" type="submit" id="art-button-wrapper" value="I donate 500 Karma, and want to become a 'Content Creator'!" />
</form>
PHP 处理程序文档
<?php
//get content out of form
$nick = $_REQUEST['username'];
$mail = $_REQUEST['mail'];
$cct = $_REQUEST['CCT'];
$motiv = $_REQUEST['motivation'];
$why = $_REQUEST['whyshouldwe'];
$ref = $_REQUEST['reference'];
$userID = $_REQUEST['UserID'];
$errors = '';
//database connection script
include "DBConnection.php";
//get connection
$con = getconnection();
//is connection available
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
//select database
mysql_select_db("brokendi_BD", $con);
//get current karma
$result = mysql_query("SELECT * FROM userpoints WHERE uid='$userID'");
$row = mysql_fetch_array($result);
$currentkarma = (int)$row['points'];
//check karma level
if ($currentkarma < 499)
{
$errors .= "\n Error: Not enough karma";
}
//check nickname
if(empty($nick))
{
$errors .= "\n Error: Username is required";
}
//check e-mail field
if(empty($mail))
{
$errors .= "\n Error: E-mail is required";
}
//check cct field
if(empty($cct))
{
$errors .= "\n Error: Content Creator Type is required";
}
//e-mail validation
if (!preg_match(
"/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/i",
$mail))
{
$errors .= "\n Error: Invalid email address";
}
//send e-mail and deduct karma
if( empty($errors))
{
$newkarma = $currentkarma-500;
mysql_query("UPDATE userpoints SET points = '$newkarma' WHERE uid='$userID'");
$to = "support@brokendiamond.org";
$email_subject = "$nick: I want to become a content creator";
$email_body = " Nickname: $nick \n Email: $mail\n Content Creator Type: $cct\n Motivation:\n $motiv\n\n Why should we accept you:\n $why\n\n reference:\n $ref";
mail($to,$email_subject,$email_body,"From: $mail");
mail($mail,"Content Creator application","Dear $nick,\n\nYour application has been recieved and will be answered as soon as we can, usually this takes less than 24 hours,\nbut occasionaly this might take us longer.\n\nKind regards,\nThe Broken Diamond Team","From: no-reply@brokendiamond.org");
header('Location: http://brokendiamond.org');
}
//close connection
mysql_close($con);
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Contact form handler</title>
</head>
<body>
<!-- This page is displayed only if there is some error -->
<?php
echo nl2br($errors);
?>
</body>
</html>