$_POST

$HTTP_POST_VARS [非推奨]

(PHP 4 >= 4.1.0, PHP 5, PHP 7)

$_POST -- $HTTP_POST_VARS [非推奨]HTTP POST 変数

説明

Content-Type に application/x-www-form-urlencoded あるいは multipart/form-data を用いた HTTP リクエストで、 HTTP POST メソッドから現在のスクリプトに渡された変数の連想配列です。

$HTTP_POST_VARS は同じ情報を持っていますが、 これはスーパーグローバルではありません (HTTP_POST_VARS$_POST は違う変数であり、PHPはそれぞれ別に扱います)。

変更履歴

バージョン 説明
4.1.0 $_POST が導入され、 $HTTP_POST_VARS は非推奨となりました。

例1 $_POST の例

<?php
echo 'Hello ' htmlspecialchars($_POST["name"]) . '!';
?>

ユーザーが name=Hannes と POST したとします。

上の例の出力は、 たとえば以下のようになります。

Hello Hannes!

注意

注意:

これは 'スーパーグローバル' あるいは自動グローバル変数と呼ばれるものです。 スクリプト全体を通してすべてのスコープで使用することができます。 関数やメソッドの内部で使用する場合にも global $variable; とする必要はありません。

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User Contributed Notes 8 notes

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215
james dot ellis at gmail dot com
8 years ago
One feature of PHP's processing of POST and GET variables is that it automatically decodes indexed form variable names.

I've seem innumerable projects that jump through extra & un-needed processing hoops to decode variables when PHP does it all for you:

Example pseudo code:

Many web sites do this:

<form ....>
<input name="person_0_first_name" value="john" />
<input name="person_0_last_name" value="smith" />
...

<input name="person_1_first_name" value="jane" />
<input name="person_1_last_name" value="jones" />
</form>

When they could do this:

<form ....>
<input name="person[0][first_name]" value="john" />
<input name="person[0][last_name]" value="smith" />
...
<input name="person[1][first_name]" value="jane" />
<input name="person[1][last_name]" value="jones" />
</form>

With the first example you'd have to do string parsing / regexes to get the correct values out so they can be married with other data in your app... whereas with the second example.. you will end up with something like:
<?php
var_dump
($_POST['person']);
//will get you something like:
array (
0 => array('first_name'=>'john','last_name'=>'smith'),
1 => array('first_name'=>'jane','last_name'=>'jones'),
)
?>

This is invaluable when you want to link various posted form data to other hashes on the server side, when you need to store posted data in separate "compartment" arrays or when you want to link your POSTed data into different record handlers in various Frameworks.

Remember also that using [] as in index will cause a sequential numeric array to be created once the data is posted, so sometimes it's better to define your indexes explicitly.
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45
darren_wheatley at hotmail dot com
2 years ago
I know it's a pretty basic thing but I had issues trying to access the $_POST variable on a form submission from my HTML page. It took me ages to work out and I couldn't find the help I needed in google. Hence this post.

Make sure your input items have the NAME attribute. The id attribute is not enough! The name attribute on your input controls is what $_POST uses to index the data and therefore show the results.
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15
woodhavenbp at yahoo dot com
1 year ago
There's an earlier note here about correctly referencing elements in $_POST which is accurate.  $_POST is an associative array indexed by form element NAMES, not IDs.  One way to think of it is like this:  element "id=" is for CSS, while element "name=" is for PHP.  If you are referring to your element ID in the POST array, it won't work.  You must assign a name attribute to your element to reference it correctly in the POST array.  These two attributes can be the same for simplicity, i.e.,
<input type="text" id="txtForm" name="txtForm">...</input>
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37
CXJ
3 years ago
Note that $_POST is NOT set for all HTTP POST operations,  but only for specific types of POST operations.  I have not been able to find documentation, but here's what I've found so far.

$_POST _is_ set for:

Content-Type: application/x-www-form-urlencoded

In other words,  for standard web forms.

$_POST is NOT set for:

Content-Type:text/xml

A type used for a generic HTTP POST operation.
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10
paul at youngish dot homelinux^org
9 years ago
For a page with multiple forms here is one way of processing the different POST values that you may receive.  This code is good for when you have distinct forms on a page.  Adding another form only requires an extra entry in the array and switch statements.

<?php

if (!empty($_POST))
{
   
// Array of post values for each different form on your page.
   
$postNameArr = array('F1_Submit', 'F2_Submit', 'F3_Submit');       

   
// Find all of the post identifiers within $_POST
   
$postIdentifierArr = array();
       
    foreach (
$postNameArr as $postName)
    {
        if (
array_key_exists($postName, $_POST))
        {
            
$postIdentifierArr[] = $postName;
        }
    }

   
// Only one form should be submitted at a time so we should have one
    // post identifier.  The die statements here are pretty harsh you may consider
    // a warning rather than this.
   
if (count($postIdentifierArr) != 1)
    {
       
count($postIdentifierArr) < 1 or
            die(
"\$_POST contained more than one post identifier: " .
              
implode(" ", $postIdentifierArr));

       
// We have not died yet so we must have less than one.
       
die("\$_POST did not contain a known post identifier.");
    }
        
    switch (
$postIdentifierArr[0])
    {
    case
'F1_Submit':
       echo
"Perform actual code for F1_Submit.";
       break;

    case
'Modify':
       echo
"Perform actual code for F2_Submit.";
       break;
          
    case
'Delete':
       echo
"Perform actual code for F3_Submit.";
       break;
    }
}
else
// $_POST is empty.
{
    echo
"Perform code for page without POST data. ";
}
?>
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1
acutclub at gmail dot com
14 days ago
See it like this: input elements are meant to be sent far away to the server with a unique reference [the name attribute] to designate that element. likewise there must be some reference pointing to that same element locally. The ID attribute is the reference for local processing, it makes the element visible to JavaScript and the CSS engine. Modern browsers issue a console warning (We are talking about Local processing here) when encountering the same id more than once because that does matter to them, but for double names they dont care, that is left to the server to worry about.
up
0
alexiskarad at gmail dot com
11 months ago
Something interesting which might help someone else:
If your input field in HTML is "disabled", even if it contains text, $_POST will not return/contain any value.
As an alternative, you can use "readonly" in your input field.
up
-3
kermit
10 months ago
As pointed out by CXJ,

$_POST is NOT set for:
Content-Type:text/xml

If you want to receive raw xml data, use
file_get_contents("php://input")
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