index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="style.css">
    <title>Temprature Convertor</title>
</head>
<body>
   <div class="main">
       <h1>Temperature convertor</h1>

        <div class="heading">
            <form id="tempcalc" onsubmit="Calculatetemp(); return false">

                <label for="temp">Enter tempreature</label>
                <input type="number" name="temp" id="temp">
                <!-- <br> -->
                <select name="temp_diff" id="temp_diff">
                    <option value="cel">Celcius</option>
                    <option value="fah">Fahrenite</option>
                    <option value="kal">kelvin</option>
                </select>
                <br>
                <input id="butt" type="submit" value="Convert" name="temp">
                <!-- <button id="butt">Convert</button> --> <br>
                <span id="resContainer1"></span><br>
                <span id="resContainer2"></span>
            </form>
            </div>
    </div>
    <script src="script.js"></script>
</body>
</html>