Untitled

User ID : [_______]
Name    : [_______]
Email   : [_______]@example.edu.com

  [Register Button]

<!DOCTYPE html>
<html>
<body>

<p>Click the button to display the value of the value attribute of the hidden input field.</p>

<input type="" id="myInput" value="" placeholder="enter email">@example.com
<br>

<button onclick="myFunction()">send</button>

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

<script>
function myFunction() {

    var y = '@example.com';
    var x =
    document.getElementById("myInput").value;
    var z = x + y;

    document.getElementById("demo").innerHTML = z;
}
</script>

</body>
</html>