d3 brush

<html>
<head>
	<title>d3::brush</title>
	<meta charset=utf-8 />
</head>
<script src='https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.6/d3.min.js'></script>
<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.1/css/bootstrap.min.css" rel="stylesheet">
<style>

body {
  font: 14px monospace;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.x.axis path {
  display: none;
}

.line {
  fill: none;
  stroke: crimson;
  stroke-width: 1.5px;
}

.brush {
  fill: lightgray;
  fill-opacity: .75;
  shape-rendering: crispEdges;
}
</style>
<body>
<div class="container">
	<h1>tambora on brush</h1>
  <hr>
  <div>
    <p><mark>Please open console for more information</mark></p>
    <h3>Reference:</h3>
    <ul>
    	<li><a href="https://github.com/mbostock/d3/wiki/SVG-Controls">d3.brush API</a></li>
    	<li><a href="https://github.com/mbostock/d3/wiki/Time-Formatting">d3.time Formatting</a></li>
    </ul>
  </div>
  <div id="timeline"></div>
  <hr>

</div>

<script type="text/javascript">
var margin = {top: 20, right: 20, bottom: 30, left: 50},
    width = 960 - margin.left - margin.right,
    height = 180 - margin.top - margin.bottom;

var parseDate = d3.time.format("%Y-%m-%d").parse;

var x = d3.time.scale()
    .range([0, width]);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left");

var line = d3.svg.line()
    .x(function(d) { return x(d.time_begin); })
    .y(function(d) { return y(d.count); })
    .interpolate("bundle");

var svg = d3.select("#timeline").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.csv("events.csv", function(error, data) {
  data.forEach(function(d) {
    d.count = +d.count;
    d.time_begin = parseDate(d.time_begin);
    
  });

x.domain(d3.extent(data, function(d) { return d.time_begin; }));
  y.domain(d3.extent(data, function(d) { return d.count; }));

svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);

svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("n count");

svg.append("path")
      .datum(data)
      .attr("class", "line")
      .attr("d", line);

// define brush control element and its events
var brush = d3.svg.brush()
    .x(x)
    .on("brushstart", brushstart)
    .on("brush", brushmove)
    .on("brushend", brushend);

// create svg group with class brush and call brush on it
var brushg = svg.append("g")
    .attr("class", "brush")
    .call(brush);

// set brush extent to rect and define objects height
brushg.selectAll("rect")
    .attr("height", height);

function brushstart() {
  // console.log('brushstart event is triggered');
}

function brushmove() {
  // console.log('the brush event is currently triggered');
}

function brushend() {
  // console.log('NOTE: brushend event is triggered');
  // console.log('Is the brush empty: ' + brush.empty());
  console.log('Extent of brush: ' +  brush.extent() );
}

});

</script>
</body>
</html>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.6/d3.min.js