<!DOCTYPE html>
<html lang="ja">
<style>
svg {
    border: solid 1px;
}
</style>

<head>
<meta charset="utf-8">
<title>D3.js(Force Layout)の練習</title>
</head>

<body>
<script src="http://d3js.org/d3.v3.js" charset="utf-8"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>

<script>
    var w = 800;
    var h = 800;

    var nodes = [];
    var links = [];
    var xlink = [];
    var link2 = [];

    var url = "https://ajax.googleapis.com/ajax/services/feed/load?v=1.0&q=http://feeds.feedburner.com/hatena/b/hotentry&num=-1";
    var proxy_url = "http://allow-any-origin.appspot.com/" + encodeURIComponent(url);

    function for_each(array, func) {
        Array.prototype.forEach.call(array, func);
    }

    function get_html(callback) {
        var hatena_hotentry_url = "http://b.hatena.ne.jp/hotentry";
        hatena_hotentry_url = "http://allow-any-origin.appspot.com/" + encodeURIComponent(hatena_hotentry_url);

        /*// var hatena_hotentry_url = "./hatena_hotentry.html"  */
        var req = new XMLHttpRequest();
        req.open("GET", hatena_hotentry_url);
        req.onreadystatechange = function() {
            if (req.readyState === 4 && req.status === 200) {
                callback(req.responseText);
                req = undefined;
            }
        };
        req.send(null);
    }

    function html_to_relation(html) {
        var doc = new DOMParser().parseFromString(html, "text/html");
        var error_tags = doc.getElementsByTagName("parsererror");
        if (error_tags.length) {
            console.log("error: ", error_tags);
            return [
                ["Parse error", "Maybe HTML is broken"]
            ];
        }

        var relation = [];
        /*// [["name", ...], ...]
         */
        var entry_elms = doc.querySelectorAll(
            "[data-track-section='default'] .entry-contents");
        for_each(entry_elms, function(entry_elm) {
            var entry_link_elm = entry_elm.querySelector(".entry-link");
            if (!entry_link_elm) {
                return;
            }

            var name_array = [];
            relation.push(name_array);
            name_array.push(entry_link_elm.title);

            console.log(entry_link_elm.href)

            var entry_meta_elm = entry_elm.nextElementSibling;
            if (!entry_meta_elm) {
                return;
            }
            for_each(entry_meta_elm.querySelectorAll("a.tag"), function(tag_elm) {
                name_array.push(tag_elm.textContent);
                name_array.push(entry_link_elm.href);
            });
        });

        return relation;
    }

    function relation_view(relation) {
        /*document.getElementById("view").textContent
           = JSON.stringify(relation, undefined, 2);
  */

        d3.json(proxy_url, function(error, json) {
            if (error) {
                return console.warn(error);
            }

            var feeds = json.responseData.feed;

            for (var x = 0; x < feeds.entries.length; x++) {
                var href = {
                    "url": feeds.entries[x].link
                };
                xlink.push(href);
            };
        });

        for (var i = 0; i < relation.length; i++) {
            if (i + 1 < relation.length) {
                var num = {
                    "source": i,
                    "target": +(i + 1)
                };
            } else {
                var num = {
                    "source": i,
                    "target": 0
                };
            }
            var list = {
                "label": relation[i][0],
                "url": relation[i][6]
            };
            nodes.push(list);
            links.push(num);
        }
        console.log(nodes)

        var force = d3.layout.force()
            .nodes(nodes)
            .links(links)
            .size([w, h])
            .linkStrength(0.1)
            .friction(0.9)
            .distance(200)
            .charge(-30)
            .gravity(0.1)
            .theta(0.8)
            .alpha(0.1)
            .start();

        /*console.log(nodes)*/
        var svg = d3.select("body").append("svg").attr({
            width: w,
            height: h
        });
        var link = svg.selectAll("line")
            .data(links)
            .enter()
            .append("line")
            .style({
                stroke: "#ccc",
                "stroke-width": 1
            });

        var node = svg.selectAll("circle")
            .data(nodes)
            .enter()
            .append("circle")
            .attr({
                r: 20,
                opacity: 0.5
            })
            .attr("xlink:href", function(d) {
                return d.url;
            })
            .style({
                fill: "red"
            })
            .call(force.drag);

        var label = svg.selectAll('text')
            .data(nodes)
            .enter()
            .append('text')
            .attr({
                "text-anchor": "middle",
                "fill": "black"
            })
            .style({
                "font-size": 11
            })
            .text(function(d) {
                return d.label;
            });

        force.on("tick", function() {
            link.attr({
                x1: function(d) {
                    return d.source.x;
                },
                y1: function(d) {
                    return d.source.y;
                },
                x2: function(d) {
                    return d.target.x;
                },
                y2: function(d) {
                    return d.target.y;
                }
            });
            node.attr({
                cx: function(d) {
                    return d.x;
                },
                cy: function(d) {
                    return d.y;
                }
            });
            label.attr({
                x: function(d) {
                    return d.x;
                },
                y: function(d) {
                    return d.y
                }
            });

        })
    }

    get_html(function(html) {
        relation_view(html_to_relation(html));
    });
</script>
</body>

</html>

上記のようなソースでforceレイアウトを描画しています。
node配列の中にlabelとurlを準備し、こちら(　http://bl.ocks.org/tag1216/76e6bba3fd1784eba83c　)を参考にさせて頂きリンクを貼れるようにしようとしましたが、上手く動作しません。
どのように訂正すればノードをクリックすればリンク先に正しく飛ぶのでしょうか？
お力添えよろしくお願いいたします。