var dt_vda_rows = 3;

dt_vda_addRow = function()
{
	dt_vda_rows++;
	var rowHtml = '<div class="row"><div class="a">Deposit after Year ' + dt_vda_rows + '</div><div class="b">$</div><div class="c"><input type="text" class="y" id="dt_vda_deposit' + dt_vda_rows + '" value="0"></div></div>';
	document.getElementById("morerows").innerHTML += rowHtml;
};

dt_vda_calculate = function()
{
	var deposits = [], investment, rate, moreYears, lastDepositYear = 0;

	try
	{
		investment = DT_F.getFormFloat( "dt_vda_investment", "Please enter the amount of your initial investment", "Please enter your initial investment as a number" );
		if ( investment < 0 ) {
			throw("Please enter an initial investment >= 0");
		}
		rate = DT_F.getFormFloat( "dt_vda_rate", "Please enter an interest rate", "Please enter the interest rate as a number" );
		if ( rate < -100 ) {
			throw("Please enter an interest rate >= -100%");
		}
		moreYears = DT_F.getFormInt( "dt_vda_moreyears", "Please enter the number of years you will invest for after your last deposit", "Please enter the number of additional years as a number", "The number of additional years was rounded to " );
		if ( moreYears < 0 || moreYears > 100 ) {
			throw("Please enter a number of additional years between 0 and 100");
		}
		for (var i=1; i<=dt_vda_rows; i++)
		{
			var dep = DT_F.getFormFloat( "dt_vda_deposit" + i, "Year " + i + " deposit is blank: must be a number", "Year " + i + " deposit must be a number" );
			if ( dep < 0 ) {
				throw("Year " + i + " deposit must be >= 0");
			}
			if ( dep != 0 ) {
				lastDepositYear = i;
			}
			deposits.push( dep );
		}
	}
	catch ( err )
	{
		alert(err);
		return;
	}

	var r = 1 + (rate / 100);
	var currAmount = investment;
	var table = [];
	table.push("Here is how your investment will grow over time:");
	table.push("<br><table cellpadding='0' cellspacing='0'>");
	table.push("<tr><th>Year</th><th>Interest</th><th>Deposits</th><th>Balance</th></tr>");
	table.push("<tr><td>start</td><td>$0</td><td>" + DT_F.formatDollars(investment) + "</td><td>" + DT_F.formatDollars(investment) + "</td></tr>");
	var y = 1;
	var totalInterest = 0;
	for ( var i=1; i<=lastDepositYear + moreYears; i++ )
	{
		var dep = 0;
		if ( i<= lastDepositYear ) {
			dep = deposits[i-1];
		}
		var interest = ( currAmount * r ) - currAmount;
		totalInterest += interest;
		currAmount = ( currAmount * r ) + dep;
		table.push("<tr><td>" + (y++) + "</td><td>" + DT_F.formatDollars(interest) + "</td><td>" + DT_F.formatDollars(dep) + "</td><td>" + DT_F.formatDollars(currAmount) + "</td></tr>");
	}
	table.push("</table>");
	var results = "After a total of " + (lastDepositYear + moreYears ) + " years, your investment will be worth <b>" +  DT_F.formatDollars(currAmount) + "</b>.<br><br>You will have earned " + DT_F.formatDollars(totalInterest) + " in interest.";
	results += "<br><br>" + table.join('');

	var x = document.getElementById("dt_vda_results");
	x.innerHTML = results;
	x.style.display = "block";
};