index.html

<!DOCTYPE html>
<html>
  <head>
    <link rel="stylesheet" href = "styles.css">
    <title>Temperature converter</title>
  </head>
  <body>
    <div class="text">
    <h1>Temperature Converter</h1>
    <p>Celcius to Fahrenheit and Vice-versa</p>
  </div>
    <div class = "box">
      <form id="tempcalc" onsubmit="calculateTemp(); return false">
      <label for="temp">Enter temperature</label>
        <input placeholder="0" type="number" name="temp" id = "temp">
        <select name="temp_diff" id="temp_diff">
          <option value="cel">°Celcius</option>
          <option value="far">°Fahrenheit</option>
        </select>
        <br>
    <input class="btn" type="submit" name="temp">
      <br>
    <span id="ans"></span>
      </form>
    </div>
    <script src="script.js"></script>
    </body>
  </html>