<!DOCTYPE html>
<html>
<body>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js" type="text/javascript"></script>
</head>
<h1>GST Calculation</h1>
<form method="post" action="">
<input type="hidden" name="mode" value="PinRequest" />
<label><b>Fee</b></label>
<input class="w3-input w3-border" name="pages" id="pages" type="text"><br><br>
<label><b>Total Amount</b></label>
<input class="w3-input w3-border" name="tot_amount" id="tot_amount" type="text">
<input type="submit" name="save" value="submit">
</form>
<script>
$(document).ready(function() {
$('#pages').keyup(function(ev) {
var total = $('#pages').val() * 1;
var tot_price = total + (total * 0.18);
var divobj = document.getElementById('tot_amount');
divobj.value = tot_price;
});
});
</script>
<body>
</html>