e9t/data.json

## data.json
{
  "nodes": [
    {"label": "i0", "layer": 1},
    {"label": "i1", "layer": 1},
    {"label": "h0", "layer": 2},
    {"label": "i2", "layer": 1},
    {"label": "h1", "layer": 2},
    {"label": "h2", "layer": 2},
    {"label": "h3", "layer": 2},
    {"label": "o0", "layer": 3}
  ]
}

## index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style>

text {
  pointer-events: none;
}

.node:hover {
  stroke: #999;
  stroke-opacity: .6;
  stroke-width: 4px;
}

.link {
  stroke: #999;
  stroke-opacity: .6;
}

</style>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script>

var width = 960,
    height = 500,
    nodeSize = 30;

var color = d3.scale.category20();

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

d3.json("data.json", function(error, graph) {
    var nodes = graph.nodes;

    // get network size
    var netsize = {};
    nodes.forEach(function (d) {
      if(d.layer in netsize) {
          netsize[d.layer] += 1;
      } else {
          netsize[d.layer] = 1;
      }
      d["lidx"] = netsize[d.layer];
    });

    // calc distances between nodes
    var largestLayerSize = Math.max.apply(
        null, Object.keys(netsize).map(function (i) { return netsize[i]; }));

    var xdist = width / Object.keys(netsize).length,
        ydist = height / largestLayerSize;

    // create node locations
    nodes.map(function(d) {
      d["x"] = (d.layer - 0.5) * xdist;
      d["y"] = (d.lidx - 0.5) * ydist;
    });

    // autogenerate links
    var links = [];
    nodes.map(function(d, i) {
      for (var n in nodes) {
        if (d.layer + 1 == nodes[n].layer) {
          links.push({"source": parseInt(i), "target": parseInt(n), "value": 1}) }
      }
    }).filter(function(d) { return typeof d !== "undefined"; });

    // draw links
    var link = svg.selectAll(".link")
        .data(links)
      .enter().append("line")
        .attr("class", "link")
        .attr("x1", function(d) { return nodes[d.source].x; })
        .attr("y1", function(d) { return nodes[d.source].y; })
        .attr("x2", function(d) { return nodes[d.target].x; })
        .attr("y2", function(d) { return nodes[d.target].y; })
        .style("stroke-width", function(d) { return Math.sqrt(d.value); });

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

    var circle = node.append("circle")
        .attr("class", "node")
        .attr("r", nodeSize)
        .style("fill", function(d) { return color(d.layer); });


    node.append("text")
        .attr("dx", "-.35em")
        .attr("dy", ".35em")
        .text(function(d) { return d.label; });
});
</script>

## thumbnail.png

      
    Raw
  

              thumbnail.png
	{
	"nodes": [
	{"label": "i0", "layer": 1},
	{"label": "i1", "layer": 1},
	{"label": "h0", "layer": 2},
	{"label": "i2", "layer": 1},
	{"label": "h1", "layer": 2},
	{"label": "h2", "layer": 2},
	{"label": "h3", "layer": 2},
	{"label": "o0", "layer": 3}
	]
	}
	<!DOCTYPE html>
	<meta charset="utf-8">
	<style>

	text {
	pointer-events: none;
	}

	.node:hover {
	stroke: #999;
	stroke-opacity: .6;
	stroke-width: 4px;
	}

	.link {
	stroke: #999;
	stroke-opacity: .6;
	}

	</style>
	<body>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
	<script>

	var width = 960,
	height = 500,
	nodeSize = 30;

	var color = d3.scale.category20();

	var svg = d3.select("body").append("svg")
	.attr("width", width)
	.attr("height", height);

	d3.json("data.json", function(error, graph) {
	var nodes = graph.nodes;

	// get network size
	var netsize = {};
	nodes.forEach(function (d) {
	if(d.layer in netsize) {
	netsize[d.layer] += 1;
	} else {
	netsize[d.layer] = 1;
	}
	d["lidx"] = netsize[d.layer];
	});

	// calc distances between nodes
	var largestLayerSize = Math.max.apply(
	null, Object.keys(netsize).map(function (i) { return netsize[i]; }));

	var xdist = width / Object.keys(netsize).length,
	ydist = height / largestLayerSize;

	// create node locations
	nodes.map(function(d) {
	d["x"] = (d.layer - 0.5) * xdist;
	d["y"] = (d.lidx - 0.5) * ydist;
	});

	// autogenerate links
	var links = [];
	nodes.map(function(d, i) {
	for (var n in nodes) {
	if (d.layer + 1 == nodes[n].layer) {
	links.push({"source": parseInt(i), "target": parseInt(n), "value": 1}) }
	}
	}).filter(function(d) { return typeof d !== "undefined"; });

	// draw links
	var link = svg.selectAll(".link")
	.data(links)
	.enter().append("line")
	.attr("class", "link")
	.attr("x1", function(d) { return nodes[d.source].x; })
	.attr("y1", function(d) { return nodes[d.source].y; })
	.attr("x2", function(d) { return nodes[d.target].x; })
	.attr("y2", function(d) { return nodes[d.target].y; })
	.style("stroke-width", function(d) { return Math.sqrt(d.value); });

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

	var circle = node.append("circle")
	.attr("class", "node")
	.attr("r", nodeSize)
	.style("fill", function(d) { return color(d.layer); });


	node.append("text")
	.attr("dx", "-.35em")
	.attr("dy", ".35em")
	.text(function(d) { return d.label; });
	});
	</script>