function loginshow(num)
{
    var currentmenu = document.getElementById("login_form");
      currentmenu.style.visibility = (currentmenu.style.visibility == 'visible')?'hidden':'visible';
}

function loginhide(num)
{
    var currentmenu = document.getElementById("login_form");
      currentmenu.style.visibility = (currentmenu.style.visibility == 'hidden')?'visible':'hidden';
}