demo form validation special - FACESOHO知行者

<!DOCTYPE HTML> 
<html>
<head>
<meta charset="UTF-8">
<title>启蒙教育(facesoho.com)</title>
<style>
.error {color:#FF0000;}
</style>
</head>
<body> 
<?php
// 定义变量并默认设置为空值
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
   if (empty($_POST["name"])) {
      $nameErr = "Name is required";
      } else {
         $name = test_input($_POST["name"]);
         // 检测名字是否只包含字母跟空格
         if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
         $nameErr = "只允许字母和空格"; 
         }
     }
   
   if (empty($_POST["email"])) {
      $emailErr = "Email is required";
   } else {
      $email = test_input($_POST["email"]);
      // 检测邮箱是否合法
      if (!preg_match("/([w-]+@[w-]+.[w-]+)/",$email)) {
         $emailErr = "非法邮箱格式"; 
      }
   }
     
   if (empty($_POST["website"])) {
      $website = "";
   } else {
      $website = test_input($_POST["website"]);
      // 检测 URL 地址是否合法
     if (!preg_match("/b(?:(?:https?|ftp)://|www.)[-a-z0-9+&@#/%?=~_|!:,.;]*[-a-z0-9+&@#/%=~_|]/i",$website)) {
         $websiteErr = "非法的 URL 的地址"; 
      }
   }
   if (empty($_POST["comment"])) {
      $comment = "";
   } else {
      $comment = test_input($_POST["comment"]);
   }
   if (empty($_POST["gender"])) {
      $genderErr = "性别是必需的";
   } else {
      $gender = test_input($_POST["gender"]);
   }
}
function test_input($data) {
   $data = trim($data);
   $data = stripslashes($data);
   $data = htmlspecialchars($data);
   return $data;
}
?>
<h2>PHP 表单验证实例</h2>
<p><span class="error">* 必需字段。</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>"> 
   名字:<input type="text" name="name">
   <span class="error">* <?php echo $nameErr;?></span>
   <br><br>
   E-mail:<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>
   备注:<textarea name="comment" rows="5" cols="40">

性别: 女男 *

您输入的内容是:";echo $name;echo "
";echo $email;echo "
";echo $website;echo "
";echo $comment;echo "
";echo $gender;?>