function calculate_gold()
        {

            var ppk = 630.74;
            var ppg = 0;
            var price = 0.0;
            var ptp = 0.0;            

            // Get the amount of grams
            var g = parseFloat(document.getElementById('grams').value);
            // Get the amount of karats
            var k = document.getElementById('karat').value;                        

            // Get the price per gram
            ppg = (ppk / 31.1035);

            // price = (PricePerGram * (Karats / 24)) * GramsToSell
            price = (ppg * (k / 24)) * g;
            // Calc dark down
            ptp = (price * 1.328);
             

            // Set form element
            document.getElementById('value').value = ptp.toFixed(2);
        }