function onProductDropDownChange(formPrefix){
    var productNo = document.getElementById(formPrefix + '_product').value;
    var titleNo = document.getElementById(formPrefix + '_title').value;

    var setUnitPrice = function(price){
        document.getElementById(formPrefix + '_unit_price').innerHTML = price;
    };

    switch(titleNo){
        case "GDTIS":{
            switch(productNo){
                case "001":
                    setUnitPrice("4,480");
                    break;
                case "002":
                    setUnitPrice("4,480");
                    break;
                case "003":
                    setUnitPrice("7,480");
                    break;
                case "004":
                    setUnitPrice("4,980");
                    break;
                case "005":
                    setUnitPrice("9,980");
                    break;
                case "006":
                    setUnitPrice("17,360");
                    break;
                case "033":
                    setUnitPrice("2,980");
                    break;
                case "008":
                    setUnitPrice("4,480");
                    break;
                case "009":
                    setUnitPrice("5,980");
                    break;
                case "010":
                    setUnitPrice("3,480");
                    break;
                case "011":
                    setUnitPrice("5,280");
                    break;
                case "012":
                    setUnitPrice("6,980");
                    break;
                case "013":
                    setUnitPrice("9,980");
                    break;
                case "014":
                    setUnitPrice("17,360");
                    break;
                case "015":
                    setUnitPrice("999");
                    break;
                case "016":
                    setUnitPrice("999");
                    break;
                case "017":
                    setUnitPrice("<span style='color:#ff6600;'><s>4,480</s> → 3,400</span>");
                    break;
                case "018":
                    setUnitPrice("<span style='color:#ff6600;'><s>2,980</s> → 1,980</span>");
                    break;
                case "022":
                    setUnitPrice("<span style='color:#ff6600;'><s>4,480</s> → 1,980</span>");
                    break;
                case "023":
                    setUnitPrice("<span style='color:#ff6600;'><s>3,480</s> → 1,980</span>");
                    break;
                case "032":
                    setUnitPrice("<span style='color:#ff6600;'><s>5,980</s> → 3,600</span>");
                    break;
                case "033":
                    setUnitPrice("2,980");
                    break;
            }
            break;
        }
        case "GDTAV":{
            switch(productNo){
                case "001":
                    setUnitPrice("2,980");
                    break;
                case "002":
                    setUnitPrice("4,480");
                    break;
                case "003":
                    setUnitPrice("5,980");
                    break;
                case "004":
                    setUnitPrice("<span style='color:#ff6600;'><s>4,480</s> → 3,400</span>");
                    break;
            }
            break;
        }
        case "GDTTC":{
            switch(productNo){
                case "001":
                    setUnitPrice("5,980");
                    break;
                case "002":
                    setUnitPrice("4,980");
                    break;
                case "003":
                    setUnitPrice("7,480");
                    break;
                case "004":
                    setUnitPrice("9,980");
                    break;
            }
            break;
        }
    }
}