网站在线工作正常，但在localhost上运行显示未定义的索引和变量

Question

having a panic here! my dissertation website works fine online, but an hour before submission i found out it doesnt work on a local host..two or 3 pages keep coming up with undefined index or variable. could anyone help? Here is a snipped of an error: Notice: Undefined index: tables in C:\Users..\Desktop\USBWebserver v8_enoot\SnysbArchive\Search.php on line 76

<?php
include 'UserFunction.php';
..html omitted..
//write connect function in here
include('Connect.php'); //Connects to database
$sql = "SHOW TABLES FROM $dbname";
$result = mysql_query($sql);

if (!$result) 
{
    echo "DB Error, could not list tables
";
    echo 'MySQL Error: ' . mysql_error();
    exit;
}
if (mysql_select_db($dbname, $conn))
{
?>
    <form method="post" action="SearchResults.php?go" id="searchform">
    In <select name="tables">
    <?php
    while ($row = mysql_fetch_row($result)) 
    {
    if ($row[0] != 'user_details' && $row[0] != 'request') 
    {
        echo '<option value="'.$row[0].'">'.$row[0].'</option>';
    }
    }
}
    ?>
    </select>
        Seach for: <input type="text" name="name"> 
    <input type="submit" name="submit" value="Search" />
</form>

<br>
<?php
$tbl=$_POST['tables'];
echo $tbl;
?>

it doesnt like this line $tbl=$_POST['tables']; thanks

Answer 1

Your local server has error reporting set to be higher then on your production server. This is resulting in you getting error messages for "lesser" errors like notices that you won't get on your production server. That's a good thing as your production server shouldn't be showing error messages will may be helpful to hackers and your local server should be telling you everything you are doing wrong, big and little, so you can build your application properly before going live.

In your case $_POST['tables'] isn't set and is being reported by your local server. It's also being caught by your production server but because of your error reporting settings you aren't being notified (except probably in your error logs).

UPDATE

To fix your error, check to see if that value exists before assigning it to a variable:

$tbl = (isset($_POST['tables'])) ? $_POST['tables'] : '';