function my_rollover(image_name){
	document[image_name].src= "images/"+image_name+"-on.jpg";
}

function my_rollout(image_name){
	document[image_name].src="images/"+image_name+"-off.jpg";
}

function toggle(img_name, display) {	
	document.getElementById(display).src= "images/display/"+img_name+".jpg";
}

function changeCaption(text) {
   if(document.getElementById) {
      document.getElementById("caption").innerHTML=text;
   }
}