Web Forms API

<!DOCTYPE html>
<html>
<body>

<form id="myCarForm">
  Favorite Car: <input type="text" name="fname" value="Volvo">
</form>

<form id="myColorForm">
  Favorite Color: <input type="text" name="favcolor" value="Blue">
</form>

<p>Click the button to display the HTML content of the form element with id="myForm".</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
function myFunction() {
  var x = document.forms.namedItem("myCarForm").innerHTML;
  document.getElementById("demo").innerHTML = x;
}
</script>

</body>
</html>