function checkBoxChanged()
{
    var iCheckedCount = 0;
    var iIdStart = 2;
    for(var i = 0; i < 50; i++)
    {
        var sElementId = 'ctl00_ContentPlaceHolder1_gvEditAlbums_ctl' + formatId(iIdStart) + '_cbxSelect';
        var element = document.getElementById(sElementId);
        if(element)
        {
            if(element.checked == true)
            {
                iCheckedCount++;
            }
            iIdStart++;
        }
        else
        {
            break;
        }
    }
    
    if(iCheckedCount > 1)
    {
        // disable all other checkboxes not checked
        iIdStart = 2;
        for(var i = 0; i < 50; i++)
        {
            var sElementId = 'ctl00_ContentPlaceHolder1_gvEditAlbums_ctl' + formatId(iIdStart) + '_cbxSelect';
            var element = document.getElementById(sElementId);
            if(element)
            {
                if(element.checked == false)
                {
                    element.disabled = true;
                }
                else
                {
                    element.disabled = false;
                }
                iIdStart++;
            }
            else
            {
                break;
            }
        }
    }
    else
    {
        // enable all check boxes
        iIdStart = 2;
        for(var i = 0; i < 50; i++)
        {
            var sElementId = 'ctl00_ContentPlaceHolder1_gvEditAlbums_ctl' + formatId(iIdStart) + '_cbxSelect';
            var element = document.getElementById(sElementId);
            if(element)
            {
                element.disabled = false;
                iIdStart++;
            }
            else
            {
                break;
            }
        }
    }
}

function formatId(iId)
{
    if(iId < 10)
    {
        return '0' + iId.toString();
    }
    else
    {
        return iId.toString();
    }
}