Untitled

<!DOCTYPE html>
<html lang="en">
<head>
<title></title>

<script type="text/javascript">

			function totalAmnt() {

			const TAXRATE = 0.09;

			var numdue =
			parseFloat(document.getElementById("numdue").value);

			var totalAmnt =
			parseFloat(document.getElementById("totalAmnt").value);


			if(document.getElementById("numdue").value == "")
			alert("Enter Amount");


			 if (isNaN(numdue))
			numdue = 0;
			alert("Number not entered.");

			}


</script>


</head>


<body>
	Amount:<br>
				<input/>

<br>
<br>
Total Due:<br>
				<input disabled="disabled" id="numdue"/>
<br>
<br>

				<button type="button" id="totalAmnt" onclick="totalamnt()">
				Total
				</button>


	</body>
</html>