function imgOn(img_name, caption) {
	var GECKO = document.getElementById? 1:0 ;
  	var NS = document.layers? 1:0 ;
  	var IE = document.all? 1:0 ;
  	
  	img_name = img_name.split(".", 1) + "";
  	var len = img_name.length;
  	// wenn das bild mehrmals referenziert ist und den Namen "bild_01.gif" hat
  	// die Endung "_01" entfernen
	
  	if(len > 3){
		if(img_name.charAt(len-3) == '_'){
			img_name = img_name.substring(0,(len-3));
		}
	}
  	img_name += "_big.jpg";
 
	
	if (GECKO){
		blubb = document.getElementById("rightbox");
		images = blubb.getElementsByTagName("img");
		for (var i = 0; i < images.length; i++){	    	  
	    		images[i].style.display='none';
	    	}
		document.getElementById("rightboxpic").style.backgroundImage = "url(fileadmin/user_upload/redakteur/" +img_name+ ")";		
		document.getElementById('caption').innerHTML = caption;
	}

 	else if (NS){
 		blubb = document.layers["rightbox"];
		images = blubb.layers["img"];
		for (var i = 0; i < images.length; i++){	    	  
	    		images[i].style.display='none';
	    	}	
		document.layers["rightboxpic"].style.backgroundImage = "url(fileadmin/user_upload/redakteur/" +img_name+ ")";
		document.layers['caption'].innerHTML = caption;
	     }

  	     else if (IE){
  	     	blubb = document.all["rightbox"];
		images = blubb.all["img"];
		for (var i = 0; i < images.length; i++){	    	  
	    		images[i].style.display='none';
	    	}	
  	     	document.all["rightboxpic"].style.backgroundImage = "url(fileadmin/user_upload/redakteur/" +img_name+ ")";			
  	     	document.all['caption'].innerHTML = caption;
	     }

}