PHP $_POST
<!DOCTYPE html> <html> <body> <form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>"> Name: <input type="text" name="fname"> <input type="submit"> </form><?php $name = $_REQUEST['fname']; echo $name; ?></body> </html>
PHP $_GET
<html> <body> <a href="test_get.php?subject=PHP&web=W3school.com.cn">测试 $GET</a> </body> </html>
<html> <body> <?php echo "Study " . $_GET['subject'] . " at " . $_GET['web']; ?> </body> </html>
什么是 $_SERVER["PHP_SELF"] 变量？
$_SERVER["PHP_SELF"] 是一种超全局变量，它返回当前执行脚本的文件名。
因此，$_SERVER["PHP_SELF"] 将表单数据发送到页面本身，而不是跳转到另一张页面。这样，用户就能够在表单页面获得错误提示信息。
什么是 htmlspecialchars() 函数？
htmlspecialchars() 函数把特殊字符转换为 HTML 实体。这意味着 < 和 > 之类的 HTML 字符会被替换为 < 和 > 。这样可防止攻击者通过在表单中注入 HTML 或 JavaScript 代码（跨站点脚本攻击）对代码进行利用。
PHP 表单的相关验证，带*提醒
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>"> Name: <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> Website: <input type="text" name="website"> <span class="error"><?php echo $websiteErr;?></span> <br><br> <label>Comment: <textarea name="comment" rows="5" cols="40"></textarea> <br><br> Gender: <input type="radio" name="gender" value="female">Female <input type="radio" name="gender" value="male">Male <span class="error">* <?php echo $genderErr;?></span> <br><br> <input type="submit" name="submit" value="Submit"> </form>
<!DOCTYPE HTML>
<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 = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "姓名是必填的";
} else {
$name = test_input($_POST["name"]);
// 检查姓名是否包含字母和空白字符
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "只允许字母和空格";
}
}
if (empty($_POST["email"])) {
$emailErr = "电邮是必填的";
} else {
$email = test_input($_POST["email"]);
// 检查电子邮件地址语法是否有效
if (!preg_match("/([w-]+@[w-]+.[w-]+)/",$email)) {
$emailErr = "无效的 email 格式";
}
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website = test_input($_POST["website"]);
// 检查 URL 地址语法是否有效（正则表达式也允许 URL 中的斜杠）
if (!preg_match("/(?:(?:https?|ftp)://|www.)[-a-z0-9+&@#/%?=~_|!:,.;]*[-a-z0-9+&@#/%=~_|]/i",$website)) {
$websiteErr = "无效的 URL";
}
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "性别是必选的";
} else {
$gender = test_input($_POST["gender"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<h2>PHP 验证实例</h2>
<p><span class="error">* 必需的字段</span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
姓名：<input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
电邮：<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>
评论：<textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
性别：
<input type="radio" name="gender" value="female">女性
<input type="radio" name="gender" value="male">男性
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="提交">
</form>
<?php
echo "<h2>您的输入：</h2>";
echo $name;
echo "<br>";
echo $email;
echo "<br>";
echo $website;
echo "<br>";
echo $comment;
echo "<br>";
echo $gender;
?>
</body>
</html>