index.html

<!DOCTYPE html>
<html>
    <head>
      <script src="primality.js"></script>
      <script src="factor.js"></script>
      <script src="eratosthenes.js"></script>
      <script type="text/javascript">

        function arraySum(arr) {
          n=0;
          for (i=0; i<arr.length; i++) {
            n+=arr[i];
          }
          return n;
        }

        function determinePrimality() {
          var test = document.getElementById("test").value;
          if (isPrime(test)) {
            document.getElementById("primality-result").innerHTML = test + " is Prime";
            document.getElementById("composite-factors").innerHTML = "";
            document.getElementById("perfect-number").innerHTML = "";
          } else {
            document.getElementById("primality-result").innerHTML = test + " is Composite";
            if (document.getElementById("extras").checked == true) {
              document.getElementById("composite-factors").innerHTML = "and its " + factors(test).length + " factors are " + factors(test).toString();
              console.log(factors(test));
              if (arraySum(factors(test)) / 2 == test) {
                document.getElementById("perfect-number").innerHTML = "And it is a <a href='#'>perfect number</a>";
              }
            }
          }
          if (document.getElementById("extras").checked == true) {
            document.getElementById("eratosthenes").innerHTML = "Here is a list of primes to " + test + ": " + eratosthenesReduced(test).toString();
          }
        }

      </script>

      <style>

        @import url('https://fonts.googleapis.com/css?family=Lobster+Two:400,400i,700,700i|Open+Sans:300,300i,400,400i,600,600i,700,700i,800,800i|Russo+One');

        h1 {
          font-family: 'Lobster Two';
          padding: 10px;
        }

        body {
          background: linear-gradient(90deg, hsl(60, 100%, 50%), hsl(50, 100%, 30%));
        }

        p {
          word-wrap: break-word;
        }

      </style>
    </head>
    <body>

      <h1>funWithPrimes<span style="font-family:'Russo One'"> Construction Zone</span></h1>
      <input id="test" placeholder="Enter a Number">
      <input type="button" onclick="determinePrimality()" value="Determine Primality">
      Extras: <input type="checkbox" id="extras">
      <p id="primality-result"></p>
      <hr>
      <p id="composite-factors"></p>
      <p id="perfect-number"></p>
      <p id="eratosthenes"></p>
      <hr>
      <h2><u>Running Notes</u></h2>
      <ul>
        <li>Make eratosthenesFull more like C version (natural decomposition)</li>
      </ul>

    </body>
</html>