function hide()
{
 for(i=0; i<hide.arguments.length; i++)
  {
     document.getElementById(hide.arguments[i]).style.display = 'none';
  }

}

function show(id)
{
  hide('d1', 'd2', 'd3'); 
  document.getElementById(id).style.display = 'block';
}

function over(id)
{
  id.getElementsByTagName("ul")[0].style.visibility="visible";
}

function out(id)
{
 id.getElementsByTagName("ul")[0].style.visibility="hidden";
}