Number Guessing Game

You have to guess a number between 1-100.

HTML

<!DOCTYPE html>
   <html lang="en">
       <head>
           <meta charset="utf-8">
           <meta name="viewport" content="width=device-width,initial-scale=1">
           <title>Homework 6</title>
          <script src="hw06.js"></script>
          <link rel="stylesheet" href="hw06.css">
      </head>
    <body onload="newgame()">
          <h1>High-low guessing game</h1>
          <div id="controls">
          <button onclick="newgame()">New game</button>
          <form onsubmit="guess(); return false;"><input id="guess_input" type="number">
          <input type="submit" value="Guess"></form>
          </div>
          <br><br>
          <div id="output"></div>
      </body>
  </html>

CSS

html {
       display: table;
       margin: auto;
   }
  
   body {
       display: table-cell;
       vertical-align: middle;
       font-family: Verdana, Geneva, Tahoma, sans-serif;
  }
  #output {
      width: 450px;
      height: 300px;
      overflow-y: auto;
      border: 4px solid black;
      border-radius: 8px;
      box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19)
  }
 
  form {
      display: inline;
  }
 
  button, input {
      border-radius: 8px;
  }
 
  h1 {
      text-align: center;
  }
 
  #controls {
      display: flex;
      justify-content: space-evenly;
  }
 
  .victory {
      font-size: 1.5em;
  }

JavaScript

var output;     // Global variable to reference the div element with id "output"
  var answer;     // This is the answer
  var guessCount = 1; // This variable counts the number of guesses
  var x; // This is the number guessed by the user
  
   // Function that returns a random number in [minVal, maxVal].
   function randomNumber(minVal, maxVal) {
       return minVal + Math.floor(Math.random() * (maxVal - minVal + 1));
   }
 
 // Function that writes a message to the output div
  function writeOutput(message) {
      if (!output) {
          output = document.getElementById("output");
      }
      output.innerHTML = message + "<br>" + output.innerHTML;
  }
 
  // Function that starts a new game
      function newgame() {
      writeOutput("I'm thinking of a number between 1   and 100...");
      
      var answer = Math.floor(Math.random() * 100 + 1);
      
      var guessCount = 0;
 
      // TODO: use the randomNumber function to pick an answer for this game.
  }
 
  // Function that checks the player's guess against the answer
  function guess() {
  var guessCount = 1;
  
  if(x == answer)
   {    
       writeOutput("Congratulations! You guessed the number correctly! "
               + guessCount + " Guesses ");
   }
   else if(x > answer) /* if guessed number is greater
                   than actual number*/ 
   {    
       guessCount++;
       writeOutput("The guess is incorrect! Try a lower number");
   }
   else
   {
       guessCount++;
       writeOutput("The guess is incorrect!! Try a higher number")
   }
  
      // TODO: look at the value of guess_input, compare it with the answer, and
      // tell the player whether the guess is too low, too high, or correct.
  }