设置$ _POST变量 [英] Setting $_POST variables

问题描述

我有一个使用POST的表格和一个变量. 我该如何在$ _POST中设置该变量，以便在提交表单后仍然可以获取该变量?

I have a form using POST, and a variable. How would I set that variable in $_POST so that after the form is submitted, I can still get the variable?

我只是尝试

$_POST['variable'] = $variable;

它最终是空的.

推荐答案

您应该将该变量作为表单中的隐藏字段放置，或使用会话变量.

You should either put that variable as an hidden field in your form, or use a session variable.

<form method="POST" action="someactionpage.php">
    <input type="hidden" name="my_var" value="<?php echo $myvar; ?>" />
    <!-- ... -->
</form>

提交表单后，使用$_POST['my_var']在 someactionpage.php 中获取它.

And get it after in someactionpage.php with $_POST['my_var'] when the form is submitted.

只需将其存储在$ _SESSION变量中

Just store it whithin the $_SESSION variable

<?php
    session_start (); // Just once at the beginning of your code
    // ...
    $_SESSION['my_var'] = $myvar;
?>

并使用

<?php
    session_start (); // Same than before
    // ...
    echo $_SESSION['my_var'];
?>

其他信息

正如在某些答案和评论中指出的那样，您应始终检查是否存在该变量，因为您不能保证有此值.只需使用 isset函数

if (isset ($_SESSION['my_var']))
    // Do stuff with $_SESSION['my_var']

或

if (isset ($_POST['my_var']))
    // Do stuff with $_POST['my_var']

Kolink 在评论中指出，可以很容易地看到和更改字段值(通过POST发送)由用户.因此，除非确实不是关键信息，否则始终希望使用会话变量.

As pointed out by Kolink in the comments, a field value (sended via POST) can be easily seen and changed by the user. So always prefer session variables unless it is really non-critical info.

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