// JavaScript Document

function calculate_payments(){
						var d 				= document;
						var results			= d.getElementById('results');
						var loan_term		= d.getElementById('loan_term');
						var loan			= d.getElementById('loan');
						var repayment		= d.getElementById('repayment');
						var interest		= d.getElementById('interest');
						var interest_rate	= d.getElementById('interest_rate');
						
						var payment			= d.getElementById('payment');
						var paymenttext		= d.getElementById('paymenttext');
						var payment_type	= d.getElementById('payment_type');
						var interest		= d.getElementById('interest');
						var repayment		= d.getElementById('repayment');
						
						n = parseInt(loan_term.value * 12);
						r = parseFloat(interest_rate.value);
						L = parseFloat(loan.value);
						if(check_form()){
							if(repayment.checked){
								results.style.display = 'block';
																		
								resultP1 = (L * r * (Math.pow((1 + (r / 1200)), n)));
								resultP2 = 1200 * (Math.pow((1 + (r / 1200)), n) - 1);
																										
								paymenttext.innerHTML = "Your Monthly payments for a repayment mortgage loan of £" + addCommas(L) +" will be "; 
								monthly = ((L * r * (Math.pow((1 + (r / 1200)), n))) / (1200 * (Math.pow((1 + (r / 1200)), n) - 1))).toFixed(2);
								payment.innerHTML = "£" + addCommas(monthly);
							}else if(interest.checked){
								results.style.display = 'block';
								interestOnly = ((L * r) / 1200).toFixed(2);
								paymenttext.innerHTML = "Your Monthly payments for a interest only mortgage loan of £" + addCommas(L) +" will be ";
								payment.innerHTML = "£" + addCommas(interestOnly);
							}
					  }
					  return false;
					}
					
					function addCommas(nStr){
						nStr += '';
						x = nStr.split('.');
						x1 = x[0];
						x2 = x.length > 1 ? '.' + x[1] : '';
						var rgx = /(\d+)(\d{3})/;
						while (rgx.test(x1)) {
							x1 = x1.replace(rgx, '$1' + ',' + '$2');
						}
						return x1 + x2;
					}
					
					function check_form(){
						var d 				= document;
						var loan_term		= d.getElementById('loan_term');
						var loan			= d.getElementById('loan');
						var repayment		= d.getElementById('repayment');
						var interest		= d.getElementById('interest');
						var interest_rate	= d.getElementById('interest_rate');
						var interest		= d.getElementById('interest');
						var repayment		= d.getElementById('repayment');
						
						if(loan_term.value==''){
							alert('Please enter the Mortgage Term');
							loan_term.focus();
							return false;
						}else if(loan.value==''){
							alert('Please enter the Mortgage Loan Amount');
							loan.focus();
							return false;
						}else if(interest_rate.value==''){
							alert('Please enter the Interest Rate');
							interest_rate.focus();
							return false;
						}else if(!interest.checked && !repayment.checked){
							alert('Please select the payment Type');
						}else{
							return true;
						}
					
					}