function validateForm() {

    if (document.dlm.select.selectedIndex < 1 &&
        document.dlm.check1.checked == false &&
        document.dlm.check2.checked == false &&
        document.dlm.check3.checked == false &&
        document.dlm.check4.checked == false &&
        document.dlm.check5.checked == false &&
        document.dlm.check6.checked == false &&
        document.dlm.check7.checked == false &&
        document.dlm.check8.checked == false) {
            //document.getElementById('errorMsg').innerHTML = '你至少必須選取一個下載項目';
            alert ('你至少必須選取一個下載項目');
            return false;
        }
    else if (document.dlm.select.selectedIndex < 1 && 
        document.getElementById('drivercheck').checked ==true) {
            //document.getElementById('errorMsg').innerHTML = '你在下載驅動程式時，必須選取一種作業系統';
            document.dlm.select.focus();
            document.dlm.select.style.border = '2px solid red';
            alert ('你在下載驅動程式時，必須選取一種作業系統');
            return false;
    }
    else {
        return true;
    }
}

function clearChecks() {
    document.dlm.check1.checked = false;
    document.dlm.check2.checked = false;
    document.dlm.check3.checked = false;
    document.dlm.check4.checked = false;
    document.dlm.check5.checked = false;
    document.dlm.check6.checked = false;
    document.dlm.check7.checked = false;
    document.dlm.check8.checked = false;
}

function calcFileSize() {
    driver = getItem();
    check1 = getChecked('check1', '455.6');
    check2 = getChecked('check2', '8.3');
    check3 = getChecked('check3', '19.3');
    check4 = getChecked('check4', '1.3');
    check5 = getChecked('check5', '964.9');
    check6 = getChecked('check6', '550.9');
    check7 = getChecked('check7', '293.1');
    check8 = getChecked('check8', '488.7');
    
    sum = eval(driver + check1 + check2 + check3 + check4 + check5 + check6 + check7 + check8);
    total = sum.toFixed(2);
    
    document.getElementById('filesize').innerHTML = total;
}


function getChecked(item, size) {
    if (document.getElementById(item).checked == true) {
        return eval(size);
    }
    else {
        return null;
    }
}

function getItem() {
    var driverSize;
    if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.13_geforce_winvista_32bit_international_whql.exe") {
       driverSize = 109;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.13_geforce_winvista_64bit_international_whql.exe") {
       driverSize = 126;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.13_geforce_winxp_32bit_international_whql.exe") {
       driverSize = 119;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.13_geforce_winxp_64bit_international_whql.exe") {
       driverSize = 129;
       return driverSize;
    }
    else {
        return null;
    }
}

function showHidePopup(hide, show) {
    Effect.Appear(show, { duration: 1.0 });
    Effect.Fade(hide, { duration: 0.5 });
    //document.getElementById(hide).style.display = 'none';
    //document.getElementById(show).style.display = '';
}

function imgSwap(id, source) {
    document.getElementById(id).src = source;
}

function slideDown(id) {
    Effect.SlideDown(id, { duration: 1.0 });

}