这应该适用于 PDO 数据库：
- 在您完成所有必填字段之前，它不会提交到您的数据库，并且还会显示所需的输入错误消息。
- 如果您忘记填写其中一个必填字段并提交，则不会清除所有字段。
我在连接中添加了一个 If 语句。
<?php
// define variables and set to empty values
$nameErr = $emailErr = $cityErr = $commentErr = $genderErr = "";
$name = $email = $city = $comment = $gender = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Please add a name";
} else {
$name = validateInput($_POST["name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]+/",$name)) {$nameErr = "Only letters and white
space allowed";}
}
if (empty($_POST["email"])) {
$emailErr = "Please add an email";
} else {
$email = validateInput($_POST["email"]);
// check if email is an email format
if (!filter_var($email, FILTER_VALIDATE_EMAIL)){
$emailErr = "Invalid email format";
}
}
if (empty($_POST["city"])) {
$cityErr = "Please add your city";
} else {
$city = validateInput($_POST["city"]);
// check if city only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$city)) {
$cityErr = "Only letters and white space allowed";
}
}
if (empty($_POST["comment"])) {
$commentErr = "Please add your comment";
} else {
$comment = validateInput($_POST["comment"]);
// check if comment only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$comment)) {
$commentErr = 'Only "/", "-", "+", and numbers';
}
}
if (empty($_POST["gender"])) {
$genderErr = "Please pick your gender";
} else {
$gender = validateInput($_POST["gender"]);
}
}
// Validate Form Data
function validateInput($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
if(!empty($_POST["name"]) && !empty($_POST["email"]) && !empty($_POST["city"]) && !empty($_POST["comment"]) && !empty($_POST["gender"]))
{
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "myDBPDO";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "INSERT INTO info (name, email, city, comment, gender)
VALUES ('$name', '$email', '$city', '$comment', '$gender')";
// use exec() because no results are returned
$conn->exec($sql);
echo "Success! Form Submitted!";
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}
$conn = null;
}
?>
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<h2>PHP Form</h2>
<p>Doesn't submit until the required fields you want are filled</p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<div class="error">
<p><span>* required field</span></p>
<div><?php echo $nameErr;?></div>
<div><?php echo $emailErr;?></div>
<div><?php echo $cityErr;?></div>
<div><?php echo $commentErr;?></div>
<div><?php echo $genderErr;?></div>
</div>
<label for="name">Name:
<input type="text" name="name" id="name" placeholder="" value="<?php echo $name;?>">
<span class="error">*</span>
</label>
<label for="email">Email:
<input type="email" name="email" id="email" placeholder="" value="<?php echo $email;?>">
<span class="error">*</span>
</label>
<label for="city">city:
<input type="text" name="city" id="city" placeholder="" value="<?php echo $city;?>">
<span class="error">*</span>
</label>
<label for="comment">comment:
<input type="text" name="comment" id="comment" value="<?php echo $comment;?>">
<span class="error">*</span>
</label>
<label for="gender">Gender:<br>
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="female") echo "checked";?> value="female">Female
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="male") echo "checked";?> value="male">Male
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="other") echo "checked";?> value="other">Other
<span class="error">*</span>
</label>
<input type="submit" name="submit" value="Submit">
</form>
</body>
</html>
如果您想将其重定向到另一个页面，请使用此选项，以便在刷新表单时不会再次将表单发送到您的 PDO 数据库。
- 它不会提交到您的数据库，并且会停留在 HOME.PHP 页面上，直到您完成所有必填字段，并且还会在 HOME.PHP 页面上显示所需的输入错误消息。
- 如果您忘记填写其中一个必填字段并提交，则不会清除所有字段。
添加了“标题（“位置：welcome.php”）；”在“$conn->exec($sql);”之后
HOME.PHP
<?php
// define variables and set to empty values
$nameErr = $emailErr = $cityErr = $commentErr = $genderErr = "";
$name = $email = $city = $comment = $gender = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "Please add a name";
} else {
$name = validateInput($_POST["name"]);
// check if name only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]+/",$name)) {$nameErr = "Only letters and white space allowed";}
}
if (empty($_POST["email"])) {
$emailErr = "Please add an email";
} else {
$email = validateInput($_POST["email"]);
// check if email is an email format
if (!filter_var($email, FILTER_VALIDATE_EMAIL)){
$emailErr = "Invalid email format";
}
}
if (empty($_POST["city"])) {
$cityErr = "Please add your city";
} else {
$city = validateInput($_POST["city"]);
// check if city only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$city)) {
$cityErr = "Only letters and white space allowed";
}
}
if (empty($_POST["comment"])) {
$commentErr = "Please add your comment";
} else {
$comment = validateInput($_POST["comment"]);
// check if comment only contains letters and whitespace
if (!preg_match("/^[a-zA-Z ]*$/",$comment)) {
$commentErr = 'Only "/", "-", "+", and numbers';
}
}
if (empty($_POST["gender"])) {
$genderErr = "Please pick your gender";
} else {
$gender = validateInput($_POST["gender"]);
}
}
// Validate Form Data
function validateInput($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
if(!empty($_POST["name"]) && !empty($_POST["email"]) && !empty($_POST["city"]) && !empty($_POST["comment"]) && !empty($_POST["gender"]))
{
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "myDBPDO";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "INSERT INTO info (name, email, city, comment, gender)
VALUES ('$name', '$email', '$city', '$comment', '$gender')";
// use exec() because no results are returned
$conn->exec($sql);
header("Location: welcome.php");
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}
$conn = null;
}
?>
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
</style>
</head>
<body>
<h2>PHP Form</h2>
<p>Doesn't submit until the required fields you want are filled</p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<div class="error">
<p><span>* required field</span></p>
<div><?php echo $nameErr;?></div>
<div><?php echo $emailErr;?></div>
<div><?php echo $cityErr;?></div>
<div><?php echo $commentErr;?></div>
<div><?php echo $genderErr;?></div>
</div>
<label for="name">Name:
<input type="text" name="name" id="name" placeholder="" value="<?php echo $name;?>">
<span class="error">*</span>
</label>
<label for="email">Email:
<input type="email" name="email" id="email" placeholder="" value="<?php echo $email;?>">
<span class="error">*</span>
</label>
<label for="city">city:
<input type="text" name="city" id="city" placeholder="" value="<?php echo $city;?>">
<span class="error">*</span>
</label>
<label for="comment">comment:
<input type="text" name="comment" id="comment" value="<?php echo $comment;?>">
<span class="error">*</span>
</label>
<label for="gender">Gender:<br>
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="female") echo "checked";?> value="female">Female
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="male") echo "checked";?> value="male">Male
<input type="radio" name="gender" <?php if (isset($gender) && $gender=="other") echo "checked";?> value="other">Other
<span class="error">*</span>
</label>
<input type="submit" name="submit" value="Submit">
</form>
</body>
</html>
WELCOME.PHP
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=\, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<h1>Success! Form Submitted!</h1>
<script type="text/javascript" src="js/main.js" ></script>
</body>
</html>