Sum Calculator in HTML

<html>
<head>
<title>Sum Calculator</title>
</head>
<body>
<form oninput="x.value=parseFloat(a.value)+parseFloat(b.value)">
  <input type="number" name="a" value="0">
  +
  <input type="number" name="b" value="0">
  =
  <output name="x"></output>
</form>
</body>
</html>