<html>
<head>
<center> <h1> Petrol Calculator</h1></center>
<script language =" javascript">
function writetext (form)
{
var KPL = form.inputbox.value;
var Fuel = form.inputbox2.value;
form.inputbox3.value =KPL * Fuel
}
</script>
</head>
<body>
<form name = "myform">
Enter Petrol Milage<br>
<input type = "text" name = "inputbox" value = ""><p><br>
Enter Amount OF Fuel:<br>
<input type = "text" name = "inputbox2" value = ""><p><br>
KiloMeters To Travel:<br>
<input type = "text" name = "inputbox3" value = ""><p><br>
<input type = "button" name = "button" value = "Display KM" onclick ="writetext(this.form)">
</body>
</html>