<?php
  $uscores = explode(".", __FILE__);
  $html = file_get_contents($uscores[0] . ".html");
  if ((isset($_POST['heading']) && isset($_POST['paragraph']))) {
    echo str_replace("My first paragraph.", $_POST['paragraph'], str_replace("My First Heading", $_POST['heading'], $html));
  } else if ((isset($_GET['heading']) && isset($_GET['paragraph']))) {
    echo str_replace("My first paragraph.", $_GET['paragraph'], str_replace("My First Heading", $_GET['heading'], $html));
  } else {
    echo $html;
  }
?>