function checkisnan(frmObj)
{
	var var_proceed = true;
	if(isNaN(frmObj.value) == true)
	{
		alert('Please use only numbers between 0 and 9');
		frmObj.value = trimlastvalue(frmObj.value);		
		var_proceed = false;
	}
	return var_proceed;	
}
function calctotaldebt(frmObj)
{
	if(checkisnan(frmObj) == true)
	{
		var var_debttotal = 0
		for(i=1;i<6;i++)
		{
			var tagname = 'debt_' + i;
			var elemt = eval(document.affordcalc[tagname].value);
			if(elemt == null)
			{	
				elemt = 0;
			}
			var_debttotal += eval(elemt);
		}	
		document.affordcalc.debttotal.value = var_debttotal;
	}
}
function trimlastvalue(frminput)
{
	var inputlength = frminput.length;
	var var_returnstring = "";
	for(i=0;i<inputlength;i++)
	{
		var_CharAt = frminput.charAt(i);
		if(isNaN(var_CharAt) == true)
		{
			var_CharAt = "";
		}
		var_returnstring += var_CharAt;
	}
	return var_returnstring;
}
function calcmaxhomeprice()
{	
	
	var var_frontratio = 30;
	var var_backratio = 36;
	var var_origfee = 1
	var var_downpayment = document.affordcalc.assets.value;
	var var_monthlyincome = (document.affordcalc.Income.value / 12);
	var var_monthlydebt = document.affordcalc.debttotal.value;
	if(var_monthlydebt == "")
	{
		var_monthlydebt = 0;
	}
	var var_powerrate = (30 * -12);
	var var_monthlyrate = (8 / 1200);
	var var_addmonthlyrate = (var_monthlyrate + 1);
	var var_power = (Math.pow(var_addmonthlyrate, (var_powerrate))); //var_powerrate)
	var var_subtract = (1 - var_power);
	var var_divide = (var_monthlyrate / var_subtract);
	var var_taxratio = (1.25/1200);
	var var_hazardratio = .000291176;
	// something is screwy in here
	var_downpayment = (var_downpayment/100);
	var var_hv = (1 /(1 - var_downpayment));
	var var_tx = var_hv * var_taxratio;
	var var_hi = var_hv * var_hazardratio;
	var var_pitifactor = (var_tx + var_hi);
	var var_lafactor = (var_pitifactor * (1/var_divide));
	var var_frpiti = parseInt((var_monthlyincome) * (var_frontratio / 100));
	var var_brminc = parseInt((var_monthlyincome) * (var_backratio / 100));
	var var_brpiti = parseInt(var_brminc) - parseInt(var_monthlydebt);
	if((var_frpiti < var_brpiti) == true)
	{
		var var_pi = (var_frpiti / (1 + var_lafactor));
	}else{
		var var_pi = (var_brpiti / (1 + var_lafactor));
	}
	var var_loanamount = (var_pi / var_divide);
	var_loanamount = (parseInt(var_loanamount/100) * 100);
	var var_homevalue = (parseInt(var_loanamount / (1 - var_downpayment)));
	var var_maxhomeprice = Math.abs(var_homevalue);
	document.affordcalc.maxhomeprice.value = roundcurrency(var_maxhomeprice);
	if(!document.affordcalc.assets.value == "")
	{
		document.affordcalc.maxdownpayment.value = roundcurrency(var_homevalue * (document.affordcalc.assets.value/100));
	}
	document.affordcalc.estclosingcosts.value = roundcurrency((var_maxhomeprice * (var_origfee/100)));
}

function roundcurrency(number)
{
	var dol=number*100;
	dol=Math.round(dol);
	var dolstring=""+dol;
	var len=dolstring.length;
	var endFig = "$"+dolstring.substring(0,len-2)+"."+dolstring.substring(len-2,len);
	return endFig;
}