function toggleLayer( whichLayer )
{
  var elem, vis;
  if( document.getElementById ) // this is the way the standards work
    elem = document.getElementById( whichLayer );
  else if( document.all ) // this is the way old msie versions work
      elem = document.all[whichLayer];
  else if( document.layers ) // this is the way nn4 works
    elem = document.layers[whichLayer];
  vis = elem.style;
  // if the style.display value is blank we try to figure it out here
  if(vis.display==''&&elem.offsetWidth!=undefined&&elem.offsetHeight!=undefined)
    vis.display = (elem.offsetWidth!=0&&elem.offsetHeight!=0)?'block':'none';
  vis.display = (vis.display==''||vis.display=='block')?'none':'block';
}

function closeLayer( whichLayer )
{
  var elem, vis;
  if( document.getElementById ) // this is the way the standards work
    elem = document.getElementById( whichLayer );
  else if( document.all ) // this is the way old msie versions work
      elem = document.all[whichLayer];
  else if( document.layers ) // this is the way nn4 works
    elem = document.layers[whichLayer];
  vis = elem.style;
  // if the style.display value is blank we try to figure it out here
  vis.display = 'none';
}

function showCat( whichCat )
{
	if( whichCat == 'cat1')
		{
			toggleLayer(whichCat);
			closeLayer('cat2');
			closeLayer('cat3');
			closeLayer('cat4');
			closeLayer('cat5');
		}
	else if ( whichCat == 'cat2')
		{
			toggleLayer(whichCat);
			closeLayer('cat1');
			closeLayer('cat3');
			closeLayer('cat4');
			closeLayer('cat5');
		}
	else if ( whichCat == 'cat3')
		{
			toggleLayer(whichCat);
			closeLayer('cat1');
			closeLayer('cat2');
			closeLayer('cat4');
			closeLayer('cat5');
		}
	else if ( whichCat == 'cat4')
		{
			toggleLayer(whichCat);
			closeLayer('cat1');
			closeLayer('cat2');
			closeLayer('cat3');
			closeLayer('cat5');
		}
	else if ( whichCat == 'cat5')
		{
			toggleLayer(whichCat);
			closeLayer('cat1');
			closeLayer('cat2');
			closeLayer('cat3');
			closeLayer('cat4');
		}
}

// JavaScript Document