function calc(i, multiple) {
	
		var s = document.getElementById("roi"+i);
		var tb = document.getElementById("tb"+i);
		var tbFixed;
		var v;
		tbFixed = tb.value.replace("$","");
		tbFixed = tbFixed.replace(",","");
		tbFixed = tbFixed.replace(" ","");

		if (isNaN(tbFixed) || tbFixed=="") {
			v = "";
			
			if (isNaN(tbFixed)) {
				$("tb"+i).value = "";		
			}
		} else {
			newtotal = Multiply(tbFixed,multiple);
			v = "$"+addCommas(formatAsMoney(newtotal));
			tb.value = addCommas(tbFixed);
		}

		$("roi"+i).value = v;

		var allInputs = Form.getInputs('f');
		
		var total = 0;
		allInputs.each(function(item) {
		  if (item.id.include("roi")) {
				val = item.value.replace("$","");
				val = val.replace(",","");
				val = val.replace(" ","");
				total = (total*1) + (val*1);
		  }
		});
		$("total").value = formatAsMoney(total);

	}
	
	function Multiply(x,y) {
		var result = x * y
		return result
	}							

	function formatAsMoney(mnt) {
		mnt -= 0;
		mnt = (Math.round(mnt*100))/100;
		return (mnt == Math.floor(mnt)) ? mnt + '.00' 
				: ( (mnt*10 == Math.floor(mnt*10)) ? 
						mnt + '0' : mnt);
	}							
	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;
	}