// JavaScript Document
/***************************
(c) 2008 www.TUFaT.com
All Rights Reserved. Please
do not re-sell/re-distribute
this software.
***************************/
function ClearInput(form){
	form.price.value="";
	form.year.value="";
	form.rate.value="";
	form.down0.value="";
	form.down_1.value="";
	form.down_3.value="";
	form.down1.value="";
	form.down2.value="";
	form.down3.value="";
	form.down4.value="";
	form.month0.value="";
	form.month_1.value="";
	form.month_3.value="";
	form.month1.value="";
	form.month2.value="";
	form.month3.value="";
	form.month4.value="";
    return true;
}

function help(helponwhat) {
    if (helponwhat == "value") {
		alert("Enter the amount you need to borrow.")
	} else if (helponwhat == "year") {
        alert("Enter the number of years you want to repay your home loans. ")
    } else if (helponwhat == "rate") {
	   alert("Parrish & Associates offers a variety of home loan products to suit your needs.");
	}
}

function CheckForm(form){
	if (form.price.value==null||form.price.value.length==0){
			alert("Please enter the amount financed for your purchase");
			return false;
	} else {
		 if (form.price.value<20000){
			alert("Please enter a price greater than 20000. Please reenter");
			return false;
		} else { 
			if (form.year.value==null||form.year.value.length==0){
			    alert("Please enter the length of your mortgage.");
                return false;
			} else { 
				if (form.rate.value<2||form.rate.value>20){
					alert("The interest rate should be between 5% and 20%.");
	                return false;
				} else {
					return true;
				}
	        }
		}
	}
}

function MakeMoney(numb){
	money='';
	for (var i=0;i<numb.value.length; i++) {
		j=i+1;
		money+=numb.value.substring(i,j);
		if (numb.value==Math.round(numb.value)) {
			pos=numb.value.length-j;
		} else { 
			pos=numb.value.length-3-j;
		}
		tmp=Math.round(pos/3);
		if (pos == tmp*3 && pos != 0) money+=",";
	}
	return money;
}

function PVIFA(annual_rate, years, period){
	var monthly_rate=annual_rate/period;
	var factor=0;
	var base_rate=1+monthly_rate;
	var denominator=base_rate;
	for (var i=0;i<(years*period);i++){
		factor+=(1/denominator);
		denominator*=base_rate;
	}
	return factor;
}

function Calculate(form){
	if (CheckForm(form)){
		down0=form.price.value*0.00;
		down_1=form.price.value*0.01;
		down_3=form.price.value*0.03;
		down1=form.price.value*0.05;
		down2=form.price.value*0.10;
		down3=form.price.value*0.15;
		down4=form.price.value*0.20;
		form.down0.value=Math.round(down0);
		form.down_1.value=Math.round(down_1);
		form.down_3.value=Math.round(down_3);
		form.down1.value=Math.round(down1);
		form.down2.value=Math.round(down2);
		form.down3.value=Math.round(down3);
		form.down4.value=Math.round(down4);
		interest_rate=(form.rate.value/100);
		monthly_factor=PVIFA(interest_rate, form.year.value, 12);
		var base_amount=form.price.value-down0;
		form.month0.value=Math.round(base_amount/monthly_factor);
		var base_amount=form.price.value-down_1;
		form.month_1.value=Math.round(base_amount/monthly_factor);
		var base_amount=form.price.value-down_3;
		form.month_3.value=Math.round(base_amount/monthly_factor);
		var base_amount=form.price.value-down1;
		form.month1.value=Math.round(base_amount/monthly_factor);
		base_amount=form.price.value-down2;
		form.month2.value=Math.round(base_amount/monthly_factor);
		base_amount=form.price.value-down3;
		form.month3.value=Math.round(base_amount/monthly_factor);
		base_amount=form.price.value-down4;
		form.month4.value=Math.round(base_amount/monthly_factor);
		form.down0.value=MakeMoney(form.down0);
		form.down_1.value=MakeMoney(form.down_1);
		form.down_3.value=MakeMoney(form.down_3);
		form.down1.value=MakeMoney(form.down1);
		form.down2.value=MakeMoney(form.down2);
		form.down3.value=MakeMoney(form.down3);
		form.down4.value=MakeMoney(form.down4);
		form.month0.value=MakeMoney(form.month0);
		form.month_1.value=MakeMoney(form.month_1);
		form.month_3.value=MakeMoney(form.month_3);
		form.month1.value=MakeMoney(form.month1);
		form.month2.value=MakeMoney(form.month2);
		form.month3.value=MakeMoney(form.month3);
		form.month4.value=MakeMoney(form.month4);
		return true;
	}
}