RockPaperScissors.php

<?php
  session_start();
  $states = array("rock", "paper", "scissors");

  if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $computerState = $states[rand(0, 2)];
    $playerState = key($_POST);

    if (!isset($_SESSION["Score"])) {
      $_SESSION["Score"] = 0;
    }

    if ($playerState == $computerState) {
      $result = "<font color=\"orange\">Draw</font>";
    } elseif ($playerState == "rock" && $computerState == "paper") {
      $result = "<font color=\"red\">You Lose</font>";
      $_SESSION["Score"] = $_SESSION["Score"] - 1;
    } elseif ($playerState == "rock" && $computerState == "scissors") {
      $result = "<font color=\"green\">You Win</font>";
      $_SESSION["Score"] = $_SESSION["Score"] + 1;
    } elseif ($playerState == "paper" && $computerState == "rock") {
      $result = "<font color=\"green\">You Win</font>";
      $_SESSION["Score"] = $_SESSION["Score"] + 1;
    } elseif ($playerState == "paper" && $computerState == "scissors") {
      $result = "<font color=\"red\">You Lose</font>";
      $_SESSION["Score"] = $_SESSION["Score"] - 1;
    } elseif ($playerState == "scissors" && $computerState == "rock") {
      $result = "<font color=\"red\">You Lose</font>";
      $_SESSION["Score"] = $_SESSION["Score"] - 1;
    } elseif ($playerState == "scissors" && $computerState == "paper") {
      $result = "<font color=\"green\">You Win</font>";
      $_SESSION["Score"] = $_SESSION["Score"] + 1;
    }

    if ($playerState == "reset_score") {
      session_unset();
      session_destroy();
      session_start();
    } else {
      $resultsHtml = "$result!<br />Computer: " . ucfirst($computerState) . "<br />You: " . ucfirst($playerState) . "<br /><br />Your Score: " . $_SESSION["Score"];
    }
  }
?>
<html>
  <head>
    <title>Rock Paper Scissors</title>
    <style>
      body {
        font-family: Helvetica;
        background-color: #ebebeb;
        text-align: center;
      }
      button {
        padding: 10px;
        margin: 10px;
        font-size: 20px;
      }
    </style>
  </head>
  <body>
    <h1>Rock Paper Scissors game</h1>
    <h6>by Thomas Jones</h6>
    <form method="post">
      <button name="rock" type="submit">Rock</button>
      <button name="paper" type="submit">Paper</button>
      <button name="scissors" type="submit">Scissors</button>
      <br /><button name="reset_score" type="submit">Reset Score</button>
    </form>
    <p><?php if ($_SERVER["REQUEST_METHOD"] == "POST") { echo $resultsHtml; } ?></p>
  </body>
</html>