How to send POST info without a form?

I have a single php file that I want to do some different things (only one at a time, based on a conditional): display a form to the user for input submit information from (above) form to database list information in database (that has been INSERTed by the above) I want this file to be able to call itself using the following code: $input = $_SERVER['PHP_SELF']."?action=INPUT"; $list = $_SERVER['PHP_SELF']."?action=LIST"; print '<a href="'.$input.'">Input a new user</a><br>'; print '<a href="'.$list.'">List all users</a>'; but I want to submit the action value as a POST rather than a GET. I then have conditionals around each of my modules that check $_POST['action'] for one of three values and only print that module if that's the action I need the file to perform. Basically I'm trying to figure out how to lump this all into one file. Obviously I could split it into three files that do each of the desired actions, but I would then also have to have a fourth file which provides a front end into it, which I don't want to do and is what got me started down this path. How can I submit POST information to a php file without using an HTML form? TIA.