Working BMI Calculator

HTML

<!DOCTYPE html>
<html>
<head>
    <title>BMI Calculator</title>
</head>
<body>

  Weight:-<input type="text" id="wtxt"><br>
  Height:-<input type="text" id="htxt"><br>
  BMI:-<input type="text" id="bmitxt"><br>

  <input type="reset" value="clear"><br>

  <button onclick="calcbmi()">Calc BMI</button>


        <script type="text/javascript">
            function calcbmi(){
                var w=parseInt(document.getElementById('wtxt').value);
                var h=parseInt(document.getElementById('htxt').value);

                var z=w/(h*h);

                document.getElementById('bmitxt').value=z;

            }
        </script>
</body>
</html>