function GetTag(TagID) {
//returns a reference to the HTML element with ID = TagID
	var Ret=document.getElementById(TagID);
	if (!Ret) alert("GetTag: tag '"+TagID+"' does not exist.");
	return Ret;
}

function ToggleExpand(ExpandID, ImagePath) {
	var ExpandButton = GetTag(ExpandID + "_expand_button");
	var ShortHTML = GetTag(ExpandID + "_short_html");
	var LongHTML = GetTag(ExpandID + "_long_html");

	if (ShortHTML.style.display == "none") {
		ShortHTML.style.display = "";
		LongHTML.style.display = "none";
		ExpandButton.src = ImagePath+ExpandImage;
	} else {
		ShortHTML.style.display = "none";
		LongHTML.style.display = "";
		ExpandButton.src = ImagePath+CollapseImage;
	}
}