function HideIdBlock(id)
{
    if (document.getElementById(id) != undefined)
    {
        document.getElementById(id).style.visibility='hidden';
        document.getElementById(id).style.display='none';
    }
}

function ShowIdBlock(id)
{
    if (document.getElementById(id) != undefined)
    {
        document.getElementById(id).style.visibility='visible';
        document.getElementById(id).style.display='block';
    }
}