// JavaScript Document
function toggleLayer( whichLayer )
{
  var elem, vis;
  if( document.getElementById ) // this is the way the standards work
  {
    elem = document.getElementById( 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)
	if ( elem.offsetWidth != 0 && elem.offsetHeight != 0 )
	{
		vis.display = 'block';
	}
	else
	{
		vis.display = 'none';		
	}
	if (  vis.display == '' || vis.display == 'block' )
	{
		vis.display = 'none';
	}
	else
	{
		vis.display = 'block'
	}
}