CI - URL Catch

It's different to handle the data on CodeIgniter using url parameter.
If your request page is like this one:
http://localhost/hello/insert/name/luna
You should catch the argument using

function insert($name = ''){

}

But when the request is comes from a form, you should catch the argument using

function insert(){

    $name = $_POST['name'];

}

CI - URL Catch