Brushable Network

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

.node {
  stroke: #fff;
  stroke-width: 1.5px;
}

.node .selected {
  stroke: red;
}

.link {
  stroke: #999;
}

</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var width = 960,
    height = 500;

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

d3.json("graph.json", function(error, graph) {
  if (error) throw error;

graph.links.forEach(function(d) {
    d.source = graph.nodes[d.source];
    d.target = graph.nodes[d.target];
  });

var node = svg.append("g")
      .attr("class", "node")
    .selectAll("circle")
    .data(graph.nodes)
    .enter().append("circle")
      .attr("r", 4)
      .attr("cx", function(d) { return d.x; })
      .attr("cy", function(d) { return d.y; });

var brush = svg.append("g")
      .attr("class", "brush")
      .call(d3.brush()
        .extent([[0, 0], [width, height]])
        .on("start brush end", brushed));

function brushed() {
    var selection = d3.event.selection;
    node.classed("selected", selection && function(d) {
      return selection[0][0] <= d.x && d.x < selection[1][0]
          && selection[0][1] <= d.y && d.y < selection[1][1];
    });
  }
});

</script>

https://d3js.org/d3.v4.min.js