function addElt(parent, elt) {
   parent.appendChild(elt);
   return elt;
}

function addNewElt(parent, type, cl, content) {
    var elt = mkElt(type, cl, content);
    parent.appendChild(elt);
    return elt;
}

function mkElt(type, cl, content) {
    var elt = document.createElement(type);
    if (cl) {
	elt.setAttribute("class", cl);
    }
    if (content) {
	if (typeof content == "string") {
	    var text = document.createTextNode(content);
	    elt.appendChild(text);
	} else if (typeof content == "object") {
	    elt.appendChild(content);
	}
    }
    return elt;
}

function currentLiID(target, current) {
    if (target == current) {
	return "currentLi";
    }
    return null;
}

function mkCurrentLiImg(pathToTop) {
    var img = mkImg(pathToTop + "/nav/images/currentLi.gif");
    return img
    }

function setID(elt, id) {
    elt.setAttribute("id", id);
}

function setClass(elt, cl) {
    elt.setAttribute("class", cl);
}

function mkImg(src) {
    var img = document.createElement("img");
    img.setAttribute("src", src);
    img.setAttribute("border", "0");
    return img;
}

function mkLink(href, content, substitution) {
    if (substitution) {
	href = substitution;
    }
    var link = mkElt("a", null, content);
    link.setAttribute("href", href);
    return link;
}


function imageRollover(img_name, img_src) {
   document[img_name].src = img_src;
}