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 = 'You must select at least one item to download';
            alert ('You must select at least one item to download');
            return false;
        }
    else if (document.dlm.select.selectedIndex < 1 && 
        document.getElementById('drivercheck').checked ==true) {
            //document.getElementById('errorMsg').innerHTML = 'You must select an operating system to download a driver';
            document.dlm.select.focus();
            document.dlm.select.style.border = '2px solid red';
            alert ('You must select an operating system to download a driver');
            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 == "178.24_geforce_winvista_32bit_international_beta.exe") {
       driverSize = 112.3;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.24_geforce_winvista_64bit_international_beta.exe") {
       driverSize = 129.6;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.24_geforce_winxp_32bit_international_beta.exe") {
       driverSize = 122.6;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.24_geforce_winxp_64bit_international_beta.exe") {
       driverSize = 132.7;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.24_geforce_winvista_32bit_english_beta.exe") {
       driverSize = 84.0;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.24_geforce_winvista_64bit_english_beta.exe") {
       driverSize = 102.1;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.24_geforce_winxp_32bit_english_beta.exe") {
       driverSize = 84.3;
       return driverSize;
    }
    else if (document.dlm.select.options[document.dlm.select.options.selectedIndex].value == "178.24_geforce_winxp_64bit_english_beta.exe") {
       driverSize = 95.9;
       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 });

}

function getHeight() {
        var math = document.body.offsetHeight/2 - 792/2;
        if(document.body.offsetHeight >= 792){
            document.getElementById('wrapper').style.top = math + 'px';
        } else {
            document.getElementById('wrapper').style.top = '0px';
        }
    }