var expand_img;
var collapse_img;

function initExcerpts(expand, collapse) {
  expand_img = expand;
  collapse_img = collapse;
}

function toggleExcerpt(div_id, img_id, event) {
	div = document.getElementById(div_id);
	img = document.getElementById(img_id);
	if (div) {
		event.cancelBubble = true;
		style = div.style;
		if (style.visibility == 'visible') {
			style.visibility = 'hidden';
			style.position = 'absolute';
			
			if (img) {
			 img.src = expand_img;
      }
		} else {
			style.visibility = 'visible';
			style.position = 'relative';
			if (img) {
			 img.src = collapse_img;
			}
		}
	}
}