未定义的索引'；邀请'；注册页面出现错误 - Undefined index 'invite' error at registration page

Undefined index 'invite' error at registration page

我在简单地输入注册页面时收到此错误

Undefined index: invite

但当我使用进入同一页面时

url?invite=2000 this error is not shown...

下面代码的第二行显示了错误。

    $mySess = JFactory::getSession();       
    $_SESSION['fromid'] = $_GET['invite'];
    $fromid = $_SESSION['fromid'];

如果url中没有使用"invite"，我如何初始化它。。。

使用isset函数，如下所示：

$mySess = JFactory::getSession();       
$_SESSION['fromid'] = isset($_GET['invite']) ? $_GET['invite'] : '';
$fromid = $_SESSION['fromid'];

这基本上是Matt的解决方案，但没有复杂的if-then-else简写。

$mySess = JFactory::getSession();       
// this value will be used if you did not pass the parameter invite to your script
$inviteDefaultValue = -1;
// isset checks if the variable exists. 
// you can also use array_key_exists("invite", $_GET)
if (isset($_GET['invite']))
{
    // $_GET['invite'] is set, so we can use it
    $_SESSION['fromid'] = $_GET['invite']);
}
else
{
    // $_GET['invite'] is not set, so use your default value here
    $_SESSION['fromid'] = $inviteDefaultValue;
}
$fromid = $_SESSION['fromid'];

http://php.net/manual/en/function.isset.php

http://php.net/manual/en/function.array-key-exists.php