Php 简明教程

PHP - Complete Form

本章将表单验证和提取 HTML 表单数据的所有概念放入 PHP 代码中。下面给出的完整表单处理代码分三个部分：开始时的 PHP 代码部分，当表单提交时寻找任何验证错误；HTML 表单，带有各种元素，例如文本字段、单选按钮、选择控件、复选框等。第三部分又是一段 PHP 代码，它呈现用户输入的数据。

PHP Error Tracking

捕获错误的代码位于整个脚本的开头。显然，这将在每次加载页面时执行。如果在表单提交后加载，则以下片段检查每个元素是否为空，电子邮件字段是否格式化良好，以及复选框是否被单击（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 Form

呈现条目表单的 HTML 脚本遵循错误捕获代码。表单设计中采用了多种元素。

<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，表单数据已提交回同一个脚本，因此表单的 action 属性设置为 $_SERVER["PHP_SELF"] 超全局。此部分还包含某些内联 PHP 代码，这些代码在各个表单控件旁边闪烁错误消息——例如，如果名称字段在提交表单时为空，则在名称文本框旁边立即显示名称必需的消息。

Display Form Data

脚本的第三部分又是一段 PHP 代码，它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>";
      }
   }
?>

当脚本从服务器的文档根目录运行时，此为表单中填写的示例数据 −

当提交时， output 呈现如下所示 −

Example

处理 HTML 表单的 PHP 的完整代码如下所示 −

<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>

它将生成以下 output −