function formatNumber(value) {
   var result = Math.floor(value) + ".";
   var cents = 100*(value - Math.floor(value))+0.5;
   result += Math.floor(cents/10);
   result += Math.floor(cents%10);
   return(result);
}

function clearCalcs(form) {
 	form.sellPrice.value="0.00";
	form.foodCost.value="0.00";
	form.serveDay.value="0";
	form.serveWeek.value="0";
	form.serveMonth.value="0";
	form.serveYear.value="0";
   form.profitDrink.value ="0.00";
   form.profitDaily.value ="0.00";
   form.profitWeekly.value ="0.00";
   form.profitMonthly.value ="0.00";
   form.profitYearly.value ="0.00";
}

function calculate(form) {
   var sellPrice = form.sellPrice.value;
   var foodCost = form.foodCost.value;
	var serveDay = form.serveDay.value;
	var serveWeek = form.serveWeek.value;
	var serveMonth = form.serveMonth.value;
	var serveYear = form.serveYear.value
	if (sellPrice < 0) {
      form.sellPrice.value = 0.00
	   sellPrice = 0.00;
   }
	var price = (sellPrice-foodCost);
   form.profitDrink.value = formatNumber(price);
   x = (price*serveDay);
   form.profitDaily.value = formatNumber(x);
   x = (price*serveDay*serveWeek);
   form.profitWeekly.value = formatNumber(x);
   x = (price*serveDay*serveWeek*serveMonth);
   form.profitMonthly.value = formatNumber(x);
   x = (price*serveDay*serveWeek*serveMonth*serveYear);
   form.profitYearly.value = formatNumber(x);
   
}