/* <![CDATA[ */
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';
}
/* ]]> */