function show_current()
{
  show_by_class('current_items_table');
  
}

function show_years()
{
  show_by_class('year');
}

function show_months()
{
  show_by_class('month');
}

function show_sites(id)
{
  show_by_class('site', id);
}

function show_items(id)
{
  //alert('showing items for'+id);
  show_by_id(id+'_table');
}

function show_by_id(id)
{
  var it = document.getElementById(id);
  var which = (it.style.display=='none' || it.style.display == '') ? 'block' : 'none';
  it.style.display = which;
}

function show_by_class(classname,node_id)
{
    var node;
    if(!node_id)
    {
      node = document.getElementsByTagName("body")[0];
    }
    else
    {
      node = document.getElementById(node_id);
    }
    if(node)
    {
      var a = [];
      var re = new RegExp('\\b' + classname + '\\b');
      var els = node.getElementsByTagName("*");
      for(var i=0,j=els.length; i<j; i++)
          if(re.test(els[i].className))
          {
            var which = (els[i].style.display == 'none' ||els[i].style.display == '' ) ? 'block' : 'none';
            els[i].style.display = which;
          }
    }
}