function calc_commissionpercent()
{

	// Rental Basis
	var RentalBasisAdvanced = document.fRental.rental_basis_advance.checked;
	// Cost ex
	var B = document.fRental.rental_cost_ex.value;
	// Deposit %
	var Ip = document.fRental.rental_depositpercent.value;
	// Advance Rental ex
	var A = document.fRental.rental_advancerental_ex.value;
	// Commission % options
	var Cp = document.fRental.rental_commissionpercent.value;;
	var Cupper = 5;
	var Clower = 7;
	
	if (RentalBasisAdvanced) {

		// set the Commission percent
		if (B >= 10000 && (Cp == Cupper || Cp == Clower))
		{
			Cp = Cupper;
			Cp = Cp.toFixed(4);
			document.fRental.rental_commissionpercent.value = Cp;
		}
		else if (Cp == Cupper || Cp == Clower)
		{
			Cp = Clower;
			Cp = Cp.toFixed(4);
			document.fRental.rental_commissionpercent.value = Cp;
		}	

	}
	else
	{
		// either the deposit % or the Advance Rental is input
		// so establish which
		if (parseFloat(Ip) > 0)
		{
			// Deposit Percent Input
			// so calculate the Advance Rental
			A = B * (Ip / 100)
		}
		
		// set the Commission percent
		if (B - A >= 10000 && (Cp == Cupper || Cp == Clower))
		{
			Cp = Cupper;
			Cp = Cp.toFixed(4);
			document.fRental.rental_commissionpercent.value = Cp;
		}
		else if (Cp == Cupper || Cp == Clower)
		{
			Cp = Clower;
			Cp = Cp.toFixed(4);
			document.fRental.rental_commissionpercent.value = Cp;
		}	
	
	}
	


	return;
}

function calc_advance()
{
	// Rental Basis
	var RentalBasisAdvanced = document.fRental.rental_basis_advance.checked;
	// Cost ex
	var B = document.fRental.rental_cost_ex.value;
	// Deposit %
	var Ip = document.fRental.rental_depositpercent.value;
	// calculate the Advance Rental
	var A;
	
	if (!RentalBasisAdvanced) {
		A = B * (Ip / 100);
		A = A.toFixed(2);
		document.fRental.rental_advancerental_ex.value = A;
		// display Deposit Percent to 4dp
		Ip = Ip.toFixed(4);
		document.fRental.rental_depositpercent.value = Ip;
		//
	}
	
	return;
}

function calc_depositpercent()
{
	// Rental Basis
	var RentalBasisAdvanced = document.fRental.rental_basis_advance.checked;
	// Cost ex
	var B = document.fRental.rental_cost_ex.value;
	// Advance Rental ex
	var A = document.fRental.rental_advancerental_ex.value;
	// calculate the Advance Rental
	if (!RentalBasisAdvanced) {
		var Ip;
		if (B > 0)
			{
			Ip = 100 * A / B;
			}
		else
			{
			alert("Please enter a Cost ex. figure first.");
			document.fRental.rental_cost_ex.focus();
			return;
			}
		Ip = Ip.toFixed(4);
		document.fRental.rental_depositpercent.value = Ip;
		// display Advance Rental to 2dp
		A = A.toFixed(2);
		document.fRental.rental_advancerental_ex.value = A;
		//
	}
	return;
}