index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>JS LAB01</title>

    <style>
      body {
        background-color: darkslategray;
        font-family: sans-serif;
      }
      .bodyContent {
        width: 70%;
        margin-inline: auto;
        padding: 3em;
        border: 2px solid black;
        background-color: white;
      }

      .bodyContent div {
        padding-bottom: 0.5em;
        margin-bottom: 2em;
        border-bottom: 2px solid lightblue;
      }

      .bodyImage {
        width: 70%;
      }

      table {
        border-collapse: collapse;
      }

      td,
      th {
        padding: 0.5em;
        border: 1px solid lightblue;
      }
    </style>

    <script defer src="script.js"></script>
  </head>
  <body>
    <div class="bodyContent">
      <h1>CPAN113 JS LAB01</h1>

      <div>
        <button id="recalcButton">ReCalc</button>
      </div>
      <div>
        <pre id="output">
The lab output goes here!
Hopefully!
        </pre>
      </div>
    </div>
  </body>
</html>

<script>
  function runLabScript() {
    const outputElement = document.getElementById("output");
    
    const ret_var = run_lab()
    outputElement.textContent = ret_var;
  }

  // ON LOAD
  document.addEventListener("DOMContentLoaded", () => {
    console.log("DO ON LOAD");
    runLabScript();
  });

  // BUTTON
  const button = document.getElementById("recalcButton");
  button.addEventListener("click", () => {
    console.log("DO RERUN");
    runLabScript();
  });
</script>