function isNumber(val)
    {
    //Returns true if val is a number defined as
    //   having an optional leading + or -.
    //   having at most 1 decimal point.
    //   otherwise containing only the characters 0-9.
	var test1 = ".+-0123456789"
	var test2 = ".0123456789"
	var c
	var decimal = false
	//The first character can be + - . or a digit.
	c = test1.indexOf(val.charAt(0))
    //Was it a decimal?
	if (c == 0)
	    decimal = true
	else if (c < 1)
		return false

	//Remaining characters can be only . or a digit, but only one decimal.
	for (var i = 1; i < val.length; i++)
		{
		//alert(val.charAt(i))
		c = test2.indexOf(val.charAt(i))
		//alert(c)
		if (c < 0)
			return false
		else
			if (c == 0)
				{
				if (decimal)		// Second decimal.
					return false
				else
					decimal = true
				}
		}
	return true
	if (!isNumber(val))
		{
    		alert("All user input must be positive numbers without dollar signs or commas")
	    	}
    }
	
function calcPmt(indexnbr,amt,intrate,term){

if((amt > "")&&(intrate > "")&&(term > ""))
	{
	PmtAmt = payment(intrate,term,amt);
	//alert ("Payment Amount = " +PmtAmt);
	
	if(indexnbr == 1){
	document.forms[0].DebtPmt1.value = PmtAmt;
	document.forms[0].include1.checked = true;
	}
	if(indexnbr == 2){
	document.forms[0].DebtPmt2.value = PmtAmt;
	document.forms[0].include2.checked = true;
	}
	if(indexnbr == 3){
	document.forms[0].DebtPmt3.value = PmtAmt;
	document.forms[0].include3.checked = true;
	}
	if(indexnbr == 4){
	document.forms[0].DebtPmt4.value = PmtAmt;
	document.forms[0].include4.checked = true;
	}
	if(indexnbr == 5){
	document.forms[0].DebtPmt5.value = PmtAmt;
	document.forms[0].include5.checked = true;
	}
	if(indexnbr == 6){
	document.forms[0].DebtPmt6.value = PmtAmt;
	document.forms[0].include6.checked = true;
	}
	if(indexnbr == 7){
	document.forms[0].DebtPmt7.value = PmtAmt;
	document.forms[0].include7.checked = true;
	}
	if(indexnbr == 8){
	document.forms[0].DebtPmt8.value = PmtAmt;
	document.forms[0].include8.checked = true;
	}
	if(indexnbr == 9){
	document.forms[0].DebtPmt9.value = PmtAmt;
	document.forms[0].include9.checked = true;
	}
	if(indexnbr == 10){
	document.forms[0].DebtPmt10.value = PmtAmt;
	document.forms[0].include10.checked = true;
	}
	}
	}
	
function computeterm(indexnbr,amt,intrate,pmt)
	{ 

	if((amt > "")&&(intrate > "")&&(pmt > ""))
	{ // start if all variables have values
	
	if (Math.abs(pmt - (amt * intrate / 1200)<0.005))
	{
		debtType = 1;
	}
	if(pmt < ((amt * intrate / 1200)- 0.005))
	{
		debtType = 2;
	}
	if(pmt > (amt * intrate / 1200))
	{
		debtType = 0;
	}
	//alert ("Debt Type = " +debtType)
	
	debtterm = mosleft(intrate,pmt,amt,debtType)
	//alert ("Debt Term = " +debtterm)
	if(indexnbr == 1){
	document.forms[0].DebtTerm1.value = debtterm;
	}
	if(indexnbr == 2){
	document.forms[0].DebtTerm2.value = debtterm;
	}
	if(indexnbr == 3){
	document.forms[0].DebtTerm3.value = debtterm;
	}
	if(indexnbr == 4){
	document.forms[0].DebtTerm4.value = debtterm;
	}
	if(indexnbr == 5){
	document.forms[0].DebtTerm5.value = debtterm;
	}
	if(indexnbr == 6){
	document.forms[0].DebtTerm6.value = debtterm;
	}
	if(indexnbr == 7){
	document.forms[0].DebtTerm7.value = debtterm;
	}
	if(indexnbr == 8){
	document.forms[0].DebtTerm8.value = debtterm;
	}
	if(indexnbr == 9){
	document.forms[0].DebtTerm9.value = debtterm;
	}
	if(indexnbr == 10){
	document.forms[0].DebtTerm10.value = debtterm;
	}
	}
	} //end function body
	
function payment(rate,mos,loanamt)
	{
	x = (1-Math.pow(1+(rate/1200),-mos))/(rate/1200);
	x = Math.round((loanamt/x*100)+0.499)/100;
	return x
	}
	

function mosleft(rate,pmt,amount,debtType)
	{
	if(debtType == 0)
	{
	y=(Math.log(pmt/amount)-Math.log((pmt/amount)-rate/1200))/Math.log(1+rate/1200)
	y = Math.round(y+.499)
	return y
	}
	if(debtType == 1)
	{
	y = "Int. Only"
	return y
	}
	if (debtType == 2)
	{
	y = "< Int Only"
	return y
	}
	}