var firstbackground = true;
function toggleToBackground( el )
{
	var whichLayer = 'main';
	  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(firstbackground ){
		firstbackground  =false;
		vis.display = 'block';
	}
	  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';
	if( vis.display == 'block' ){
		if( splitString( el.src ) == 'en.gif' ){
			el.src = 'fileadmin/images/hintergrundbild_zeigen_en.gif';
		}else{
			el.src = 'fileadmin/images/hintergrundbild_zeigen.gif';
		}
		
	}else{
		if( splitString( el.src ) == 'en.gif' ){
			el.src = 'fileadmin/images/inhalt_zeigen_en.gif';
		}else{
			el.src = 'fileadmin/images/inhalt_zeigen.gif';
		}
		
	}
}

function splitString( string )
{
	var tmp = string.split("_");
	tmp = tmp[tmp.length-1];
	return tmp;
}