Below script is not working in my project

Question

   

<script language="javascript" type="text/javascript">

function sum() {

var txtFirstNumberValue = document.getElementById('txtrd').value;

var txtsecondNumberValue = document.getElementById('txtintalment').value;

var txtthirdNumberValue = document.getElementById('txtprd').value;

var txtfourNumberValue = document.getElementById('Penality').value;

var txtFiveNumberValue = document.getElementById('txtint').value;

var txtsixNumberValue = document.getElementById('txtsbint').value;

var result = (parseFloat(txtFirstNumberValue) + parseFloat(txtSecondNumberValue) + parseFloat(txtthirdNumberValue) + parseFloat(txtfourNumberValue) + parseFloat(txtFiveNumberValue) + parseFloat(txtSecondNumberValue) + parseFloat(txtsixNumberValue)).toFixed(2);

if (!isNaN(result)) {

document.getElementById('txttp').value = result;

}

}

 

This script is not running in my project 

</script>