多個選擇/輸入框可在PHP中進行POST

Question

我正在嘗試做一個簡單的表單，該表單具有兩個textareas，以及兩個1表單的下拉列表。 我正在嘗試保存POST的值，但是它不起作用，我不斷得到：

Notice: Undefined index: team2
Notice: Undefined index: players2

我的POST頁面是這樣的：

$team1 = $_POST["team1"];
$team2 = $_POST["team2"];
$str1 = $_POST["players1"];  
$str2 = $_POST["players2"];

我的形式是這樣的：

<form action="cap_update.php" method="post">
To:
<select name="team1">
<option value="Anaheim">Anaheim</option>
<option value="Arizona">Arizona</option>
<option value="Boston">Boston</option>
</select><br><br>
<textarea rows="5" cols="80" name="players1"></textarea>
<br><br>
To:
<select name="team2">
<option value="Anaheim">Anaheim</option>
<option value="Arizona">Arizona</option>
<option value="Boston">Boston</option>
</select><br><br>
<textarea rows="5" cols="80" name="players2"></textarea>
<br><br>
<input type="submit" value="Submit trade!">
</form>

Answer 1

<?php
if(isset($team1))
{
$team1 = $_POST["team1"];
$team2 = $_POST["team2"];
$str1 = $_POST["players1"];  
$str2 = $_POST["players2"];
}
print_r($_POST);

?>
<form action="index.php" method="post">
To:
<select name="team1">
<option value="Anaheim">Anaheim</option>
<option value="Arizona">Arizona</option>
<option value="Boston">Boston</option>
</select><br><br>
<textarea rows="5" cols="80" name="players1"></textarea>
<br><br>
To:
<select name="team2">
<option value="Anaheim">Anaheim</option>
<option value="Arizona">Arizona</option>
<option value="Boston">Boston</option>
</select><br><br>
<textarea rows="5" cols="80" name="players2"></textarea>
<br><br>
<input type="submit" value="Submit trade!">
</form>



use isset to check

otherwise you can use 
error_reporting(E_ERROR | E_PARSE);
E_ERROR


    <?php
error_reporting(E_ERROR | E_PARSE);
 $team1 = $_POST["team1"];
 $team2 = $_POST["team2"];
 $str1 = $_POST["players1"];  
 $str2 = $_POST["players2"];
?>
<form action="index.php" method="post">
To:
<select name="team1">
<option value="Anaheim">Anaheim</option>
<option value="Arizona">Arizona</option>
<option value="Boston">Boston</option>
</select><br><br>
<textarea rows="5" cols="80" name="players1"></textarea>
<br><br>
To:
<select name="team2">
<option value="Anaheim">Anaheim</option>
<option value="Arizona">Arizona</option>
<option value="Boston">Boston</option>
</select><br><br>
<textarea rows="5" cols="80" name="players2"></textarea>
<br><br>
<input type="submit" value="Submit trade!">
</form>

Answer 2

由於您有四個變量，因此如果在if條件語句中檢查isset（$ team1），則在其他任何變量為空的情況下都會引發錯誤。

相反，您可以使用三元運算符。 例子如下

<?php
     $team1 = (isset($_POST["team1"]))?$_POST["team1"]:'';
     $team2 = (isset($_POST["team2"]))?$_POST["team2"]:'';
     $players1 = (isset($_POST["players1"]))?$_POST["players1"]:'';
     $players2 = (isset($_POST["players2"]))?$_POST["players2"]:'';
?>