Changing a value in $_POST

 
$_POST['name'] = trim($_POST['name']);

if (strlen($_POST['name']) == 0) {
    $errors[] = "Your name is required.";
}

1.	Basic PHP form processing
2.	if else to check posted variables
3.	Verifying a required element
4.	Superglobals vs. Globals
5.	Testing a required field
6.	Set Cookie Data

Changing a value in $_POST : _POST « Form « PHP