function toc()
{
    var toc = document.getElementById("toc");
    var entries = document.getElementsByTagName("a");
    var n = entries.length;

    var anks = new Array(n);
    for (var i = 0; i < n; i++) {
        anks[i] = entries[i].getAttribute("name");
    }

    var h3 = document.createElement("h3");
    h3.appendChild(document.createTextNode("Table of Contents"));
    toc.appendChild(h3);

    var div = document.createElement("div");
    div.setAttribute("id", "navcontainer")
    var ul = document.createElement("ul");
    div.appendChild(ul);
    toc.appendChild(div);
    for (var i = 0; i < n; i++) {
        if (anks[i] != null && anks[i].length > 0) {
            var a = document.createElement("a");
            a.appendChild(document.createTextNode(anks[i]));
            a.setAttribute("href", "#" + anks[i]);
            var li = document.createElement("li")
            li.appendChild(a);
            ul.appendChild(li);
        }
    }
}