错误消息未以php形式显示

Question

如果用户将任何内容留空，则不会显示我的错误消息。 它只是将我带到输入空白的操作页面。 为什么我的错误不显示？ 谢谢。

<p><span class="error">* required field.</span></p>
<form name="form2" method="post" action="favorites.php"> 
Name: <input type="text" name="name" value="<?php echo $name;?>">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
Favorite Season:
<input type="radio" name="season" value="winter">Winter
<input type="radio" name="season" value="spring">Spring
<input type="radio" name="season" value="summer" checked>Summer
<input type="radio" name="season" value="fall">Fall
<span class="error">* <?php echo $seasonErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>

Your name is: <?php echo $_POST["name"]; ?><br>
Your favorite season is: <?php echo $_POST["season"]; ?><br>
<?php
$nameErr =  $seasonErr = "";
$name =  $season  = "";

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

if (empty($_POST["season"])) {
$seasonErr = "Season is required";
} else {
$season = test_input($_POST["season"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>

Answer 1

原因是，您的PHP位于表格下方。 将其放在HTML表单上方。

旁注：这回答了这个问题，但并未涵盖您在初始页面加载时应该获得未定义索引通知的事实，具体取决于服务器错误报告级别的设置方式。

<?php
$nameErr =  $seasonErr = "";
$name =  $season  = "";

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

if (empty($_POST["season"])) {
$seasonErr = "Season is required";
} else {
$season = test_input($_POST["season"]);
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>

<p><span class="error">* required field.</span></p>
<form name="form2" method="post" action="favorites.php"> 
Name: <input type="text" name="name" value="<?php echo $name;?>">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
Favorite Season:
<input type="radio" name="season" value="winter">Winter
<input type="radio" name="season" value="spring">Spring
<input type="radio" name="season" value="summer" checked>Summer
<input type="radio" name="season" value="fall">Fall
<span class="error">* <?php echo $seasonErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">
</form>

Your name is: <?php echo $_POST["name"]; ?><br>
Your favorite season is: <?php echo $_POST["season"]; ?><br>

---

• 因此，最好检查是否设置了任何内容/不为空。

参考文献：

• http://php.net/manual/en/function.error-reporting.php
• http://php.net/manual/zh/function.isset.php
• http://php.net/manual/zh/function.empty.php