PHP - 完整表单

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本章将表单验证和提取 HTML 表单数据到 PHP 代码中的所有概念都整合在一起。下面给出的完整表单处理代码分为三个部分：开头是一个 PHP 代码部分，用于在提交表单时查找任何验证错误，HTML 表单包含各种元素，如文本字段、单选按钮、选择控件、复选框等。第三部分又是 PHP 代码，用于呈现用户输入的数据。

PHP 错误跟踪

捕获错误的代码位于整个脚本的开头。显然，每次加载页面时都会执行此代码。如果在提交表单后加载页面，则以下部分检查每个元素是否为空、电子邮件字段格式是否正确以及是否选中了复选框（表示用户同意条款）。

<?php

   // define variables and set to empty values
   $nameErr = $emailErr = $genderErr = $websiteErr = "";
   $name = $email = $gender = $class = $course = $subject = "";

   if ($_SERVER["REQUEST_METHOD"] == "POST") {
      if (empty($_POST["name"])) {
         $nameErr = "Name is required";
      } else {
         $name = test_input($_POST["name"]);
      }

      if (empty($_POST["email"])) {
         $emailErr = "Email is required";
      } else {
         $email = test_input($_POST["email"]);
		 
         // check if e-mail address is well-formed
         if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            $emailErr = "Invalid email format"; 
         }
      }

      if (empty($_POST["course"])) {
         $course = "";
      } else {
         $course = test_input($_POST["course"]);
      }

      if (empty($_POST["class"])) {
         $class = "";
      } else {
         $class = test_input($_POST["class"]);
      }

      if (empty($_POST["gender"])) {
         $genderErr = "Gender is required";
      } else {
         $gender = test_input($_POST["gender"]);
      }

      if (empty($_POST["subject"])) {
         $subjectErr = "You must select one or more subjects";
      } else {
         $subject = $_POST["subject"];	
      }
   }

   function test_input($data) {
      $data = trim($data);
      $data = stripslashes($data);
      $data = htmlspecialchars($data);
      return $data;
   }
?>

HTML 表单

呈现输入表单的 HTML 脚本位于错误捕获代码之后。表单设计中使用了各种表单元素。

<h2>Absolute Classes Registration Form</h2>
<p><span class = "error">* required field.</span></p>
<form method = "POST" action = "<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
   <table>
      <tr>
         <td>Name:</td>
         <td>
            <input type = "text" name = "name">
            <span class = "error">* <?php echo $nameErr;?></span>
         </td>
      </tr>
      <tr>
         <td>E-mail: </td>
         <td>
            <input type = "text" name = "email">
            <span class = "error">* <?php echo $emailErr;?></span>
         </td>
      </tr>
      <tr>
         <td>Time:</td>
         <td>
            <input type = "text" name = "course">
            <span class = "error"><?php echo $websiteErr;?></span>
         </td>
      </tr>
      <tr>
         <td>Classes:</td>
         <td><textarea name = "class" rows = "5" cols = "40"></textarea></td>
      </tr>
      <tr>
         <td>Gender:</td>
         <td>
            <input type = "radio" name = "gender" value = "female">Female
            <input type = "radio" name = "gender" value = "male">Male
            <span class = "error">* <?php echo $genderErr;?></span>
         </td>
      </tr>
      <tr>
         <td>Select:</td>
         <td>
            <select name = "subject[]" size = "4" multiple>
               <option value = "Android">C</option>
               <option value = "Java">Java</option>
               <option value = "C#">C#</option>
               <option value = "Data Base">C++</option>
               <option value = "Hadoop">PHP</option>
               <option value = "VB script">Python</option>
            </select>
         </td>
      </tr>
      <tr>
         <td>Agree</td>
         <td><input type = "checkbox" name = "checked" value = "1"></td>
         <?php if(!isset($_POST['checked'])){ ?>
            <span class = "error">* <?php echo "You must agree to terms";?></span>
         <?php } ?> 
      </tr>
      <tr>
         <td>
            <input type = "submit" name = "submit" value = "Submit"> 
         </td>
      </tr>
   </table>
</form>

请注意，表单数据会提交回同一个脚本，因此表单的 action 属性设置为 $_SERVER["PHP_SELF"] 超全局变量。此部分还包含某些内联 PHP 代码，这些代码会在相应的表单控件旁边显示错误消息，例如，如果在提交表单时名称字段为空，则在名称文本框旁边显示“名称必填”消息。

显示表单数据

脚本的第三部分又是 PHP 代码，用于回显用户提交的每个表单字段的值。

<?php
   if ($_SERVER["REQUEST_METHOD"] == "POST") {
      echo "<h2>Your given values are as :</h2>";
      echo ("<p><b>Name</b> : $name</p>");
      echo ("<p><b>Email address</b> : $email</p>");
      echo ("<p><b>Preffered class time</b> : $course</p>");
      echo ("<p><b>Class info</b> : $class </p>");
      echo ("<p><b>Gender</b> : $gender</p>");
      echo "<p><b>Subjcts Chosen:</b><p>";
      if (!empty($subject)) { 
         echo "<ul>";
         for($i = 0; $i < count($subject); $i++) {
            echo "<li>$subject[$i]</u/li>";
         }
         echo "</ul>";
      }
   }
?>

以下是当从服务器的文档根文件夹运行脚本时，在表单中填写的一些示例数据：

PHP Complete Form 1

提交后，输出如下所示：

PHP Complete Form 2

示例

PHP 处理 HTML 表单的完整代码如下：

<html>
<head>
   <style>
      .error {color: #FF0000;}
   </style>
</head>
<body>
   <?php
   
      // define variables and set to empty values
      $nameErr = $emailErr = $genderErr = $websiteErr = "";
      $name = $email = $gender = $class = $course = $subject = "";

      if ($_SERVER["REQUEST_METHOD"] == "POST") {
         if (empty($_POST["name"])) {
            $nameErr = "Name is required";
         }else {
            $name = test_input($_POST["name"]);
         }

         if (empty($_POST["email"])) {
            $emailErr = "Email is required";
         } else {
            $email = test_input($_POST["email"]);

            // check if e-mail address is well-formed
            if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
               $emailErr = "Invalid email format"; 
            }
         }

         if (empty($_POST["course"])) {
            $course = "";
         } else {
            $course = test_input($_POST["course"]);
         }

         if (empty($_POST["class"])) {
            $class = "";
         } else {
            $class = test_input($_POST["class"]);
         }

         if (empty($_POST["gender"])) {
            $genderErr = "Gender is required";
         } else {
            $gender = test_input($_POST["gender"]);
         }

         if (empty($_POST["subject"])) {
            $subjectErr = "You must select one or more subjects";
         } else {
            $subject = $_POST["subject"];	
         }
      }

      function test_input($data) {
         $data = trim($data);
         $data = stripslashes($data);
         $data = htmlspecialchars($data);
         return $data;
      }
   ?>
   <h2>Absolute Classes Registration Form</h2>
   <p><span class = "error">* required field.</span></p>
   <form method = "POST" action = "<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
      <table>
         <tr>
            <td>Name:</td>
            <td>
               <input type = "text" name = "name">
               <span class = "error">* <?php echo $nameErr;?></span>
            </td>
         </tr>
         <tr>
            <td>E-mail: </td>
            <td>
               <input type = "text" name = "email">
               <span class = "error">* <?php echo $emailErr;?></span>
            </td>
         </tr>
         <tr>
            <td>Time:</td>
            <td> 
               <input type = "text" name = "course">
               <span class = "error"><?php echo $websiteErr;?></span>
            </td>
         </tr>
         <tr>
            <td>Classes:</td>
            <td><textarea name = "class" rows = "5" cols = "40"></textarea></td>
         </tr>
         <tr>
            <td>Gender:</td>
            <td>
               <input type = "radio" name = "gender" value = "female">Female
               <input type = "radio" name = "gender" value = "male">Male
               <span class = "error">* <?php echo $genderErr;?></span>
            </td>
         </tr>
         <tr>
            <td>Select:</td>
            <td>
               <select name = "subject[]" size = "4" multiple>
                  <option value = "C">C</option>
                  <option value = "Java">Java</option>
                  <option value = "C#">C#</option>
                  <option value = "c++">C++</option>
                  <option value = "PHP">PHP</option>
                  <option value = "Python">Python</option>
               </select>
            </td>
         </tr>
         <tr>
            <td>Agree</td>
            <td><input type = "checkbox" name = "checked" value = "1"></td>
            <?php if(!isset($_POST['checked'])){ ?>
               <span class = "error">* <?php echo "You must agree to terms";?></span>
            <?php } ?> 
         </tr>
         <tr>
            <td>
               <input type = "submit" name = "submit" value = "Submit"> 
            </td>
         </tr>
      </table>
   </form>
   <?php
      if ($_SERVER["REQUEST_METHOD"] == "POST") {
         echo "<h2>Your given values are as :</h2>";
         echo ("<p><b>Name</b> : $name</p>");
         echo ("<p><b>Email address</b> : $email</p>");
         echo ("<p><b>Preffered class time</b> : $course</p>");
         echo ("<p><b>Class info</b> : $class </p>");
         echo ("<p><b>Gender</b> : $gender</p>");
         echo "<p><b>Subjcts Chosen:</b><p>";
         if (!empty($subject)) { 
            echo "<ul>";
            for($i = 0; $i < count($subject); $i++) {
               echo "<li>$subject[$i]</u/li>";
            }
            echo "</ul>";
         }
      }
   ?>
</body>
</html>

它将产生以下输出：

PHP Complete Form 1
打印页面
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