PHP - $_POST

Quiz

The $_POST variable in PHP is a super global array that collects form data after submitting an HTML form using the POST method. It is particularly useful for securely sending data and receiving user input.

What is $_POST?

$_POST is a built-in PHP array. It stores data received from an HTML form using the POST method.This data is not visible in the URL, making it more secure than the GET method.

Syntax

Here is the syntax we can use to define $_POST −

$_POST['key']

Here 'key' is the name of the form input field.

Key Points about $_POST

$_POST is one of the predefined or superglobal variables in PHP. It is an associative array of key-value pairs passed to a URL by the HTTP POST method that uses URLEncoded or multipart/form-data content-type in the request.

$_POST is a superglobal variable, which means it can be accessed from any point in the script without being marked global.
Associative array of key-value pairs.
POST data is not displayed in the URL, making it more secure for sensitive information like as passwords or personal details.
It is compatible with forms that employ URLEncoded or multipart/form-data content.
$HTTP_POST_VARS is an old version of $_POST that should not be used.
The simplest way to transmit data to the server is to modify the HTML form's method attribute to POST.

Example: HTML Form (hello.html)

Assuming that the URL in the browser is "http://localhost/hello.php", method=POST is set in a HTML form "hello.html" as below −

<html>
<body>
   <form action="hello.php" method="post">
      <p>First Name: <input type="text" name="first_name"/> </p>
      <p>Last Name: <input type="text" name="last_name" /> </p>
      <input type="submit" value="Submit" />
   </form>
</body>
</html>

The "hello.php" script (in the document root folder) for this exercise is as follows:

<?php
   echo "<h3>First name: " . $_POST['first_name'] . "<br /> " . 
   "Last Name: " . $_POST['last_name'] . "</h3>";
?>

Now, open http://localhost/hello.html in your browser. You should get the following output on the screen −

As you press the Submit button, the data will be submitted to "hello.php" with the POST method.

You can also mix the HTML form with PHP code in hello.php, and post the form data to itself using the "PHP_SELF" variable −

<html>
<body>
   <form action="<?php echo $_SERVER['PHP_SELF'];?>" method="post">
      <p>First Name: <input type="text" name="first_name"/> </p> <br />
      <p>Last Name: <input type="text" name="last_name" /></p>
      <input type="submit" value="Submit" />
   </form>
   <?php
      echo "<h3>First Name: " . $_POST['first_name'] . "<br /> " . 
      "Last Name: " . $_POST['last_name'] . "</h3>";
   ?>
</body>
</html>

It will produce the following output −

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