The $_POST Function

The built-in $_POST function is used to collect values from a form sent with method="post".
Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.
Note: However, there is an 8 Mb max size for the POST method, by default (can be changed by setting the post_max_size in the php.ini file).
Example
< form action="welcome.php" method="post" >
Name:
Age:
< input type="submit" / >
< /form >
When the user clicks the "Submit" button, the URL will look like this:
http://www.w3schools.com/welcome.php
The "welcome.php" file can now use the $_POST function to collect form data (the names of the form fields will automatically be the keys in the $_POST array):
Welcome < ?php echo $_POST["fname"]; ? >!

You are < ?php echo $_POST["age"]; ? > years old.