PHP 完整表单实例

<html>
<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 = "名字是必需的。";
   }else{
       $name = test_input($_POST["name"]);
        // 检测名字是否只包含字母跟下划线
        if (!preg_match("/^[a-zA-Z_]*$/",$name)) {
            $nameErr = "只允许字母和下划线";
        }
   }
   
   if (empty($_POST["email"])){
       $emailErr="邮箱是必需的。";
   }else{
       $email = test_input($_POST["email"]);
       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"]);
       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="性别是必须的。";
   }else{
       $gender = test_input($_POST["gender"]);
   }

}

function test_input($data)
{
 $data = trim($data);
 $data = stripslashes($data);
 $data = htmlspecialchars($data);
 return $data;
}
?>
<style>
   .error
   { text-align:"center";color:red;}
</style>

<p><span class="error">* 必填字段。</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"></textarea><br/><br/>

   性别：<input type="radio" name="gender" value="female">女
         <input type="radio" name="gender" value="male">男
        <span class="error">* <?php echo $genderErr;?></span>
   <br/><br/>
   <input type="submit" name="submit" value="Submit">
</form>

<?php
echo "<h2>您输入的内容是:</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>