php - 访问 $_POST 时出现未定义索引错误

Question

我一直在尝试解决这个问题，但它给了我同样的错误:

Notice: Undefined index: items in C:\xampp\htdocs\shop.php on line 9

Notice: Undefined index: body in C:\xampp\htdocs\shop.php on line 24

这是我的代码:

<form action="" method="post">
    <input type="radio" name="items" value="fed" /> Fed<br />
    <input type="radio" name="items" value="body" /> Body<Br>
    <input type="submit" name="submit"><br>
</form> 

<?php
if(isset($_POST['submit'])) {
     $items = $_POST['items'];
     if($items=="fed") {
         echo "You choose feds";    
         die();
     }
     else
         echo "<Form action='' method='POST'>
         <select name='body'>
         <option value='head'>Head</option>
         </select>
         <input type='submit' name='submit' value='submit' /><br />
         </form>";

 if(isset($_POST['submit'])) {
    $body = $_POST['body'];
    $connect = mysql_connect("localhost","root","")or die(mysql_error());
    mysql_select_db("feds",$connect)or die(mysql_error());
    
    $merchandise = mysql_query("SELECT * FROM merchandise WHERE body_part='$body' ")or     die(mysql_error());

    while($row = mysql_fetch_array($merchandise)) {
        echo $row['item'];  
        echo "<bR>";
    }
}


} 
?>

Answer 1

错误消息表明您正在访问不存在的数组项!

但一般来说，您应该检查这些变量是否存在(即使您确定表单已发送):

$items = isset($_POST['items']) ? $_POST['items'] : outputError('...');

请修复您的 SQL 注入(inject)安全漏洞!!

$body = mysql_real_escape_string( $_POST['body'] );

也请考虑升级到MySQLi或PDO!关于这些主题有很多很好的资源。