function showForm(id)
{
    if(document.getElementById(id).style.display == "block")
    {
      document.getElementById(id).style.display = "none";
      document.getElementById(id).style.visibility = "hidden";
    }
    else
    {    
      document.getElementById(id).style.display = "block";
      document.getElementById(id).style.visibility = "visible";
    }
}