<!DOCTYPE HTML>
<html>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<head>
<style>
.error {
color: #FF0000;
}
</style>
</head>
<body>
<?php
// 定义变量并设置为空值
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "姓名是必填的";
} else {
$name = test_input($_POST["name"]);
// 检查姓名是否包含字母和空白字符
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "只允许字母和空格";
}
}
if (empty($_POST["email"])) {
$emailErr = "电邮是必填的";
} else {
$email = test_input($_POST["email"]);
// 检查电子邮件地址语法是否有效
if (!preg_match("/([w-]+@[w-]+.[w-]+)/",$email)) {
$emailErr = "无效的 email 格式";
}
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website = test_input($_POST["website"]);
// 检查 URL 地址语法是否有效（正则表达式也允许 URL 中的斜杠）
if (!preg_match("/(?:(?:https?|ftp)://|www.)[-a-z0-9+&@#/%?=~_|!:,.;]*[-a-z0-9+&@#/%=~_|]/i",$website)) {
$websiteErr = "无效的 URL";
}
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "性别是必选的";
} else {
$gender = test_input($_POST["gender"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP 验证实例</h2>
<p>
<span class="error">* 必需的字段</span>
</p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']);?>">
姓名：<input type="text" name="name"> <span class="error">*
<?php echo $nameErr;?>
</span> <br>
<br> 电邮：<input type="text" name="email"> <span
class="error">* <?php echo $emailErr;?></span> <br>
<br> 网址：<input type="text" name="website"> <span
class="error">
<?php echo $websiteErr;?>
</span> <br>
<br> 评论：
<textarea name="comment" rows="5" cols="40"></textarea>
<br>
<br> 性别： <input type="radio" name="gender" value="female">女性
<input type="radio" name="gender" value="male">男性 <span
class="error">* <?php echo $genderErr;?></span> <br>
<br> <input type="submit" name="submit" value="提交">
</form>
<?php
echo "<h2>您的输入：</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>
From:http://www.w3school.com.cn/php/php_form_complete.asp