Visualizing a parse tree with d3.js
<p>I've been trying to obtain a visual representation of a parse tree by generating an HTML file that uses <code>d3.js</code> to draw a tree. The file looks like this:</p>

<pre><code>&lt;!DOCTYPE html&gt;
&lt;meta charset="utf-8"&gt;
&lt;head&gt;&lt;title&gt; Tree Visualization &lt;/title&gt;&lt;/head&gt;
&lt;script src="https://d3js.org/d3.v3.min.js"&gt;&lt;/script&gt;

&lt;script type="text/javascript"&gt;
    function drawTree(o) {
        d3.select("#"+o.divID).select("svg").remove() 

        var viz = d3.select("#"+o.divID)
            .append("svg")
            .attr("width", o.width)
            .attr("height", o.height)  

        var vis = viz.append("g")
            .attr("id","treeg")
            .attr("transform", "translate("+ o.padding +","+ o.padding +")") 

        var tree = d3.layout.tree()
            .size([o.width - (2 * o.padding), o.height - (2 * o.padding)]);

        var diagonal = d3.svg.diagonal()
            .projection(function(d) { return [d.x, d.y]; });

        var nodes = tree.nodes(o.treeData);

        var link = vis.selectAll("pathlink")
            .data(tree.links(nodes)).enter()
            .append("path")
            .attr("class", "link")
            .attr("d", diagonal)

        var node = vis.selectAll("g.node")
            .data(nodes).enter()
            .append("g")
            .attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; })

        node.append("circle")
            .attr("r", 10)
            .style("fill", function(d) { return (d.children) ? "#E14B3B" : "#1C8B98" });

        node.append("svg:text")
            .attr("dx", function(d) { return d.children ? 0 : 0; })
            .attr("dy", function(d) { return d.children ? 5 : 5; })
            .attr("text-anchor", function(d) { return d.children ? "middle" : "middle"; })
            .style("fill", "white").text(function(d) { return d.name; })
    }
 &lt;/script&gt;

&lt;body onLoad="drawTree({divID: 'viz', width: 600, height: 400, padding: 50, treeData: {name: 'S', children: [{name: 'S', children: [{name: 'S', children: [{name: 'S', children: [{name: 'x'}]}, {name: 'S', children: [{name: 'y'}]}, {name: '*'}]}, {name: 'S', children: [{name: '1'}]}, {name: '+'}]}, {name: 'S', children: [{name: 'S', children: [{name: '1'}]}, {name: '-'}]}, {name: '+'}]}})"&gt;
&lt;div id="viz"&gt;&lt;/div&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>

<p>What I want it to look like:
<img src="https://i.stack.imgur.com/GBqbQ.png" alt="this"></p>

<p>What it currently looks like:
<img src="https://i.stack.imgur.com/9xNuq.png" alt="this"></p>

<p>I'm completely new to <code>d3.js</code> and, to be honest, the code is taken from an example and only modified by me. I managed to get to this point this way, but I just can't figure out where it goes wrong.</p>

<p>I'd appreciate every bit of help. Thanks in advance!</p>