function CalculateSavings()
        {
            var result = document.getElementById('gasresult');
            var dist = document.getElementById('distance');
            var price = document.getElementById('price');
            var mpg = document.getElementById('mpg');
            
            if (!IsNumeric(dist.value) || !IsNumeric(price.value) || !IsNumeric(mpg.value))
            {
                result.innerHTML = "Please enter a numeric value.";
                return;
            }
            
            var total = (dist.value / mpg.value) * price.value;
            result.innerHTML = 'Total cost: $' + roundNumber(total, 2);
            document.getElementById('savings').value = roundNumber(total, 2);
        }
        
        function CalculateCalories()
        {
            var result = document.getElementById('calresult');
            var weight = document.getElementById('weight');
            var mins = document.getElementById('minutes');
            
            
            if (!IsNumeric(weight.value) || !IsNumeric(mins.value))
            {
                result.innerHTML = "Please enter a numeric value.";
                return;
            }
            
            var total = ((mins.value / 60) * 3.6306) * weight.value;
            result.innerHTML = 'Calories burned: ~' + roundNumber(total, 2);
        }
        
         function CalculatePayoff()
        {
            var result = document.getElementById('payresult');
            var cost = document.getElementById('cost');
            var savings = document.getElementById('savings');
            var days = document.getElementById('days');
            
            
            if (!IsNumeric(cost.value) || !IsNumeric(savings.value) || !IsNumeric(days.value))
            {
                result.innerHTML = "Please enter a numeric value.";
                return;
            }
            
            var total = cost.value / (savings.value * days.value);           
            var d = new Date();
            d.setDate(d.getDate() + roundNumber(total,0) * 7);
            
            result.innerHTML = 'Time to payoff: ' + roundNumber(total, 2) + ' weeks. Your bike will be paid off on ' + d.toLocaleDateString() + '.';
        }
        
        function roundNumber(num, dec) 
        {
	        var result = Math.round(num*Math.pow(10,dec))/Math.pow(10,dec);
	        return result;
        }
        
        function IsNumeric(strString)
        {
            var strValidChars = "0123456789.-";
            var strChar;
            var blnResult = true;

            if (strString.length == 0) 
                return false;

               for (i = 0; i < strString.length && blnResult == true; i++)
               {
                    strChar = strString.charAt(i);
                    if (strValidChars.indexOf(strChar) == -1)
                    {
                        blnResult = false;
                    }
               }
           return blnResult;
        }