<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<!DOCTYPE html>
<html>
<title>MPH to KPH Speed Converter</title>
<body>
<h2>Speed Converter</h2>
<p>Type a value in the MPH field to convert the value to KPH:</p>
<p>
<label>MPH</label>
<input id="inputMPH" type="number" placeholder="MPH" oninput="speedConverter(this.value)" onchange="speedConverter(this.value)">
</p>
<p>KPH: <span id="outputKPH"></span></p>
<script>
function speedConverter(valNum) {
document.getElementById("outputKPH").innerHTML=valNum*1.609344;
}
</script>
</body>
</html>