santiaago/barchart.html

## barchart.html
<!DOCTYPE html>
<meta charset="utf-8">
<title>Bar Chart with Negative Values</title>
<style>

.bar.positive {
  fill: #B9E397;
}

.bar.negative {
  fill: #D46A6A;
}

.bar.neutral {
  fill: #7282AA;
}

.axis text {
  font: 10px sans-serif;
}

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

</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 30, right: 10, bottom: 10, left: 10},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

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

var y = d3.scale.ordinal()
    .rangeRoundBands([0, height], .2);

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

var svg = d3.select("body").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.tsv("barChartData.tsv", type, function(error, data) {
  x.domain(d3.extent(data, function(d) { return d.value; })).nice();
  y.domain(data.map(function(d) { return d.name; }));

  svg.selectAll(".bar")
      .data(data)
    .enter().append("rect")
      .attr("class", function(d) {
          if (d.value < 0){
              return "bar negative";
          } else {
	      console.log(d.name);
	      if(d.name == 'neutral'){
		return "bar neutral";
	      }
	      return "bar positive";
          }
       })
      .attr("x", function(d) { return x(Math.min(0, d.value)); })
      .attr("y", function(d) { return y(d.name); })
      .attr("width", function(d) { return Math.abs(x(d.value) - x(0)); })
      .attr("height", y.rangeBand());

  svg.append("g")
      .attr("class", "x axis")
      .call(xAxis);

  svg.append("g")
      .attr("class", "y axis")
    .append("line")
      .attr("x1", x(0))
      .attr("x2", x(0))
      .attr("y2", height);

});

function type(d) {
  d.value = +d.value;
  return d;
}

</script>

## gistfile1.txt
name	value
positive	50
negative	-30
neutral	20
	<!DOCTYPE html>
	<meta charset="utf-8">
	<title>Bar Chart with Negative Values</title>
	<style>

	.bar.positive {
	fill: #B9E397;
	}

	.bar.negative {
	fill: #D46A6A;
	}

	.bar.neutral {
	fill: #7282AA;
	}

	.axis text {
	font: 10px sans-serif;
	}

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

	</style>
	<body>
	<script src="http://d3js.org/d3.v3.min.js"></script>
	<script>

	var margin = {top: 30, right: 10, bottom: 10, left: 10},
	width = 960 - margin.left - margin.right,
	height = 500 - margin.top - margin.bottom;

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

	var y = d3.scale.ordinal()
	.rangeRoundBands([0, height], .2);

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

	var svg = d3.select("body").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.tsv("barChartData.tsv", type, function(error, data) {
	x.domain(d3.extent(data, function(d) { return d.value; })).nice();
	y.domain(data.map(function(d) { return d.name; }));

	svg.selectAll(".bar")
	.data(data)
	.enter().append("rect")
	.attr("class", function(d) {
	if (d.value < 0){
	return "bar negative";
	} else {
	console.log(d.name);
	if(d.name == 'neutral'){
	return "bar neutral";
	}
	return "bar positive";
	}
	})
	.attr("x", function(d) { return x(Math.min(0, d.value)); })
	.attr("y", function(d) { return y(d.name); })
	.attr("width", function(d) { return Math.abs(x(d.value) - x(0)); })
	.attr("height", y.rangeBand());

	svg.append("g")
	.attr("class", "x axis")
	.call(xAxis);

	svg.append("g")
	.attr("class", "y axis")
	.append("line")
	.attr("x1", x(0))
	.attr("x2", x(0))
	.attr("y2", height);

	});

	function type(d) {
	d.value = +d.value;
	return d;
	}

	</script>