Hello All! I've just started with java a couple of months ago, and was wondering if anyone could tell me what's wrong here. I've written the code spot on according to instructions except I can't get the amount of interest to get calculated and displayed

Code:
<HTML>

<HEAD>

<TITLE>Interest Rate</TITLE>

<SCRIPT>

var interestRate = 0;

var response;

var amountInPounds;

var interest;

function twoDPs(anyNumber)

{

    return Math.round (100 * anyNumber) / 100

}; 



function setInterestRate()

{

	InterestRate = parseInt(window.prompt('Please enter the rate of Interest Rate of your choosing' + ''), 10)

};



function displayInterestRate()

{

	document.write('<BR>' + 'Current interest rate is ' + interestRate + '%')	

};



function calculateInterest(numberOfPounds) 

{
interest = numberOfPounds * interestRate / 100;
interest = twoDPs(interest); // or interest = interest.toFixed(2);
}; 


setInterestRate();

displayInterestRate();

document.write('<BR><BR><BR><BR>'); 


response = window.prompt('Do you want to calculate the interest on an amount of money (Y/N)? ','');

while(response == 'Y' || response == 'y')

{

	amountInPounds = window.prompt('Enter amount in Pounds ','');

	interest = calculateInterest(amountInPounds);

	document.write(' '+ amountInPounds + ' attracts ' + interest + ' interest');

	document.write('<BR><BR><BR>');  

	response = window.prompt('Do you want to calculate the interest for another amount (Y/N)? ','')	

}



</SCRIPT>

</HEAD>



<BODY>

</BODY>

</HTML>