Question

我遇到第4,5,6行的问题，一切正常，数据被发送到数据库以及输出结果但是我在加载页面时收到此消息。

Undefined index: name in C:\xampp\htdocs\xampp\site\comment.php on line 4

Notice: Undefined index: comment in C:\xampp\htdocs\xampp\site\comment.php on line 5

Notice: Undefined index: submit in C:\xampp\htdocs\xampp\site\comment.php on line 6

再次感谢，任何帮助将不胜感激:) 这是代码，非常感谢能提前帮助我的人

<?php
mysql_connect("localhost","root","");
mysql_select_db("commentbox");

$name= $_POST["name"];
$comment= $_POST["comment"];
$submit= $_POST["submit"];

$dbLink = mysql_connect("localhost", "root", "Broadband74");
    mysql_query("SET character_set_client=utf8", $dbLink);
    mysql_query("SET character_set_connection=utf8", $dbLink);

if($submit)
{
    if($name&&$comment)
    {
        mysql_query("INSERT INTO commenttable (name,comment) VALUES ('$name','$comment') ");
    }
    else
    {
        echo "please fill out all fields";
    }
}
?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Comment box</title>
</head>

<body>
<center>
<form action="comment.php" method="POST">
<table>
<tr><td>Name: <br><input type="text" name="name"/></td></tr>
<tr><td colspan="2">Comment: </td></tr>
<tr><td colspan="5"><textarea name="comment" rows="10" cols="50"></textarea></td></tr>
<tr><td colspan="2"><input type="submit" name="submit" value="Comment"></td></tr>
</table>
</form>
<?php
$dbLink = mysql_connect("localhost", "root", "");
    mysql_query("SET character_set_results=utf8", $dbLink);
    mb_language('uni');
    mb_internal_encoding('UTF-8');

$getquery=mysql_query("SELECT * FROM commenttable ORDER BY id DESC");
while($rows=mysql_fetch_assoc($getquery))
{
    $id=$rows["id"];
    $name=$rows["name"];
    $comment=$rows["comment"];
    echo $name . '<br/>' . '<br/>' . $comment . '<br/>' . '<br/>' . '<hr size="1"/>'
;}
?>

</body>
</html>

Answer 1

<?php
mysql_connect("localhost","root","");
mysql_select_db("commentbox");

if(isset($_POST["name"]){
$name= $_POST["name"];
}
if(isset($_POST["comment"]){
$comment= $_POST["comment"];
}
if(isset($_POST["submit"]){
$submit= $_POST["submit"];
}

$dbLink = mysql_connect("localhost", "root", "Broadband74");
    mysql_query("SET character_set_client=utf8", $dbLink);
    mysql_query("SET character_set_connection=utf8", $dbLink);

if($submit)
{
if($name&&$comment)
{
mysql_query("INSERT INTO commenttable (name,comment) VALUES ('$name','$comment') ");
}
else
{
echo "please fill out all fields";
}
}
?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Comment box</title>
</head>

<body>
<center>
<form action="comment.php" method="POST">
<table>
<tr><td>Name: <br><input type="text" name="name"/></td></tr>
<tr><td colspan="2">Comment: </td></tr>
<tr><td colspan="5"><textarea name="comment" rows="10" cols="50"></textarea></td></tr>
<tr><td colspan="2"><input type="submit" name="submit" value="Comment"></td></tr>
</table>
</form>
<?php
$dbLink = mysql_connect("localhost", "root", "");
    mysql_query("SET character_set_results=utf8", $dbLink);
    mb_language('uni');
    mb_internal_encoding('UTF-8');

$getquery=mysql_query("SELECT * FROM commenttable ORDER BY id DESC");
while($rows=mysql_fetch_assoc($getquery))
{
$id=$rows["id"];
$name=$rows["name"];
$comment=$rows["comment"];
echo $name . '<br/>' . '<br/>' . $comment . '<br/>' . '<br/>' . '<hr size="1"/>'
;}
?>

</body>
</html>

Answer 2

首次加载页面时，尚未绑定到请求的POST数据，因此在提交表单之前它已失败。您可以检查是否使用isset（）设置了值，您可以明确地处理错误：

http://php.net/manual/en/language.exceptions.php

或者，您可以将表单和代码放在不同的页面上进行处理。

Answer 3

您需要使用具有mysqli_或PDO功能的参数，但是：

<?php
mysql_connect("localhost","root","");
mysql_select_db("commentbox");

$dbLink = mysql_connect("localhost", "root", "Broadband74");
    mysql_query("SET character_set_client=utf8", $dbLink);
    mysql_query("SET character_set_connection=utf8", $dbLink);

if($_POST["submit"])
{
    if( (isset($_POST["name"]) && !empty($_POST["name"])) &&
        (isset($_POST["comment"]) && !empty($_POST["name"])) )
    {
        $name= $_POST["name"];
        $comment= $_POST["comment"];
        mysql_query("INSERT INTO commenttable (name,comment) VALUES ('$name','$comment') ");
    }
    else
    {
        echo "please fill out all fields";
    }
}

Answer 4

您必须先检查您的表单是否已提交：

if(isset($_POST['submit']))
{    
    mysql_connect("localhost","root","");
    mysql_select_db("commentbox");

    $name= $_POST["name"];
    $comment= $_POST["comment"];
    $submit= $_POST["submit"];

    $dbLink = mysql_connect("localhost", "root", "Broadband74");
    mysql_query("SET character_set_client=utf8", $dbLink);
    mysql_query("SET character_set_connection=utf8", $dbLink);

    if($name&&$comment)
    {
        mysql_query("INSERT INTO commenttable (name,comment) VALUES ('$name','$comment') ");
    }
    else
    {
        echo "please fill out all fields";
    }
}

Answer 5

每次加载页面时都会执行PHP代码。在第一次加载时，未给出表单输入，并且未设置这些值。但是你的脚本试图使用$_POST['field']，因为PHP不知道这些字段，它只会引发Undefined Index错误。

这个问题的解决方案实际上非常简单。使用isset()：

<?php

if(isset($_POST['submit']) { //checking if form was submitted

mysql_connect("localhost","root","");
mysql_select_db("commentbox");

$name = isset($_POST['name']) ? $_POST['name'] : null; 
$comment= isset($_POST['comment']) ? $_POST['comment'] : null; 
$submit= isset($_POST["submit"]) ? $_POST["submit"] : null;

$dbLink = mysql_connect("localhost", "root", "Broadband74");
    mysql_query("SET character_set_client=utf8", $dbLink);
    mysql_query("SET character_set_connection=utf8", $dbLink);

if($submit)
{
    if($name&&$comment)
    {
        mysql_query("INSERT INTO commenttable (name,comment) VALUES ('$name','$comment') ");
    }
    else
    {
        echo "please fill out all fields";
    }
}
?>

php评论部分在我的网站上

5 个答案: