本章将表单验证和 HTML 表单数据提取的所有概念放入 PHP 代码中。
下面给出的完整表单处理代码包含三个部分：开头 PHP 代码部分，用于在提交表单时查找任何验证错误，带有各种元素（如文本字段、单选按钮、选择控件、复选框等）的 HTML 表单。第三部分又是一个 PHP 代码，它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任务。如果在提交表单后加载，则以下段将检查每个元素是否为空，电子邮件字段是否格式正确，并单击复选框（指示用户同意条款）。
<?php
// 定义变量并设置为空值
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $class = $course = $subject = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "姓名为必填项";
} else {
$name = test_input($_POST["name"]);
}
if (empty($_POST["email"])) {
$emailErr = "电子邮件是必填项";
} else {
$email = test_input($_POST["email"]);
// 检查电子邮件地址的格式是否正确
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "电子邮件格式无效";
}
}
if (empty($_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 = "性别是必填项";
} else {
$gender = test_input($_POST["gender"]);
}
if (empty($_POST["subject"])) {
$subjectErr = "您必须选择一个或多个选项";
} else {
$subject = $_POST["subject"];
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
HTML 表单
呈现入口表单的 HTML 脚本遵循错误捕获代码。在表单设计中采用了各种元素。
<h2>启科普注册表</h2>
<p><span class = "error">* 必填字段.</span></p>
<form method = "POST" action = "<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<table>
<tr>
<td>性名:</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>时间:</td>
<td>
<input type = "text" name = "course">
<span class = "error"><?php echo $websiteErr;?></span>
</td>
</tr>
<tr>
<td>班级:</td>
<td><textarea name = "class" rows = "5" cols = "40"></textarea></td>
</tr>
<tr>
<td>性别:</td>
<td>
<input type = "radio" name = "gender" value = "女性">女性
<input type = "radio" name = "gender" value = "男性">男性
<span class = "error">* <?php echo $genderErr;?></span>
</td>
</tr>
<tr>
<td>选择:</td>
<td>
<select name = "subject[]" size = "4" multiple>
<option value = "Android">C</option>
<option value = "Java">Java</option>
<option value = "C#">C#</option>
<option value = "Data Base">C++</option>
<option value = "Hadoop">PHP</option>
<option value = "VB script">Python</option>
</select>
</td>
</tr>
<tr>
<td>同意</td>
<td><input type = "checkbox" name = "checked" value = "1"></td>
<?php if(!isset($_POST['checked'])){ ?>
<span class = "error">* <?php echo "你必须同意条款";?></span>
<?php } ?>
</tr>
<tr>
<td>
<input type = "submit" name = "submit" value = "Submit">
</td>
</tr>
</table>
</form>
请注意，表单数据被提交回同一个脚本，因此表单的 action 属性设置为 $_SERVER[“PHP_SELF”] 超全局变量。这部分还包含某些内联 PHP 代码，这些代码会在相应的表单控件之外闪烁错误消息 - 例如，如果在提交表单时 name 字段为空，则 Name 提示消息就在 Name 文本框旁边。
显示表单数据
脚本的第三部分再次是一个 PHP 代码，它回显用户提交的每个表单字段的值。
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
echo "<h2>您的给定值如下:</h2>";
echo ("<p><b>姓名</b> : $name</p>");
echo ("<p><b>Email 地址</b> : $email</p>");
echo ("<p><b>优先上课时间</b> : $course</p>");
echo ("<p><b>班级信息</b> : $class </p>");
echo ("<p><b>性别</b> : $gender</p>");
echo "<p><b>已选择子主题:</b><p>";
if (!empty($subject)) {
echo "<ul>";
for($i = 0; $i < count($subject); $i++) {
echo "<li>$subject[$i]</u/li>";
}
echo "</ul>";
}
}
?>
例子
PHP 处理 HTML 表单的完整代码如下 -
<html>
<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 = $class = $course = $subject = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "姓名为必填项";
}else {
$name = test_input($_POST["name"]);
}
if (empty($_POST["email"])) {
$emailErr = "Email为必填项";
} else {
$email = test_input($_POST["email"]);
// 检查电子邮件地址的格式是否正确
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "无效的 email 地址";
}
}
if (empty($_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 = "性别为必填项";
} else {
$gender = test_input($_POST["gender"]);
}
if (empty($_POST["subject"])) {
$subjectErr = "您必须选择一个或多个科目";
} else {
$subject = $_POST["subject"];
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>启科普班级注册表</h2>
<p><span class = "error">* 必填字段.</span></p>
<form method = "POST" action = "<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<table>
<tr>
<td>姓别:</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>上课时间:</td>
<td>
<input type = "text" name = "course">
<span class = "error"><?php echo $websiteErr;?></span>
</td>
</tr>
<tr>
<td>班别:</td>
<td><textarea name = "class" rows = "5" cols = "40"></textarea></td>
</tr>
<tr>
<td>性别:</td>
<td>
<input type = "radio" name = "gender" value = "女性">女性
<input type = "radio" name = "gender" value = "男性">男性
<span class = "error">* <?php echo $genderErr;?></span>
</td>
</tr>
<tr>
<td>选择科目:</td>
<td>
<select name = "subject[]" size = "4" multiple>
<option value = "C">C</option>
<option value = "Java">Java</option>
<option value = "C#">C#</option>
<option value = "c++">C++</option>
<option value = "PHP">PHP</option>
<option value = "Python">Python</option>
</select>
</td>
</tr>
<tr>
<td>同意</td>
<td><input type = "checkbox" name = "checked" value = "1"></td>
<?php if(!isset($_POST['checked'])){ ?>
<span class = "error">* <?php echo "你必须同意条款";?></span>
<?php } ?>
</tr>
<tr>
<td>
<input type = "submit" name = "submit" value = "Submit">
</td>
</tr>
</table>
</form>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
echo "<h2>您的给定值如下 :</h2>";
echo ("<p><b>姓名</b> : $name</p>");
echo ("<p><b>Email 地址</b> : $email</p>");
echo ("<p><b>优先上课时间</b> : $course</p>");
echo ("<p><b>班级信息</b> : $class </p>");
echo ("<p><b>性别</b> : $gender</p>");
echo "<p><b>已选择科目:</b><p>";
if (!empty($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 -
