function hideLayers() { 

  var divs = new Array('bystate','bylocation');
  var element, vis;
  for (i=0; i<divs.length; i++){
	  if( document.getElementById )  {element = document.getElementById(divs[i]);}
	  else if( document.all ) {element = document.all[divs[i]];}
	  else if( document.layers ) {element = document.divs[layers[i]];}

	  vis = element.style; // if the style.display value is blank we try to figure it out here
	  vis.display = 'none';
  }

}

function showLayer( whichLayer )
{
 
 hideLayers();
 var element, el, vis;

  if( document.getElementById ) el = document.getElementById( whichLayer );
  else if( document.all ) el = document.all[whichLayer];
  else if( document.layers ) el = document.layers[whichLayer];
  vis = el.style; 
  if(vis.display==''&&el.offsetWidth!=undefined&&el.offsetHeight!=undefined)
    vis.display = (el.offsetWidth!=0&&el.offsetHeight!=0)?'block':'none';
  vis.display = (vis.display==''||vis.display=='block')?'none':'block';
}