Histograms in JavaScript

How to make a D3.js-based histogram in JavaScript. Seven examples of colored, horizontal, and normal histogram bar charts.

New to Plotly?

Plotly is a free and open-source graphing library for JavaScript. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

Basic Histogram

var x = [];
for (var i = 0; i < 500; i ++) {
	x[i] = Math.random();
}

var trace = {
    x: x,
    type: 'histogram',
  };
var data = [trace];
Plotly.newPlot('myDiv', data);

Horizontal Histogram

var y = [];
for (var i = 0; i < 500; i ++) {
	y[i] = Math.random();
}

var data = [
  {
    y: y,
    type: 'histogram',
	marker: {
    color: 'pink',
	},
  }
];
Plotly.newPlot('myDiv', data);

Overlaid Histogram

var x1 = [];
var x2 = [];
for (var i = 1; i < 500; i++)
{
	k = Math.random();
	x1.push(Math.random() + 1);
	x2.push(Math.random() + 1.1);
}
var trace1 = {
  x: x1,
  type: "histogram",
  opacity: 0.5,
  marker: {
     color: 'green',
  },
};
var trace2 = {
  x: x2,
  type: "histogram",
  opacity: 0.6,
  marker: {
     color: 'red',
  },
};

var data = [trace1, trace2];
var layout = {barmode: "overlay"};
Plotly.newPlot('myDiv', data, layout);

Stacked Histograms

var x1 = [];
var x2 = [];
for (var i = 0; i < 500; i ++) {
	x1[i] = Math.random();
	x2[i] = Math.random();
}

var trace1 = {
  x: x1,
  type: "histogram",
};
var trace2 = {
  x: x2,
  type: "histogram",
};
var data = [trace1, trace2];
var layout = {barmode: "stack"};
Plotly.newPlot('myDiv', data, layout);

Colored and Styled Histograms

var x1 = [];
var x2 = [];
var y1 = [];
var y2 = [];
for (var i = 1; i < 500; i++)
{
  k = Math.random();
  x1.push(k*5);
  x2.push(k*10);
  y1.push(k);
  y2.push(k*2);
}
var trace1 = {
  x: x1,
  y: y1,
  name: 'control',
  autobinx: false,
  histnorm: "count",
  marker: {
    color: "rgba(255, 100, 102, 0.7)",
     line: {
      color:  "rgba(255, 100, 102, 1)",
      width: 1
    }
  },
  opacity: 0.5,
  type: "histogram",
  xbins: {
    end: 2.8,
    size: 0.06,
    start: .5
  }
};
var trace2 = {
  x: x2,
  y: y2,
  autobinx: false,
  marker: {
          color: "rgba(100, 200, 102, 0.7)",
           line: {
            color:  "rgba(100, 200, 102, 1)",
            width: 1
    }
       },
  name: "experimental",
  opacity: 0.75,
  type: "histogram",
  xbins: {
    end: 4,
    size: 0.06,
    start: -3.2

  }
};
var data = [trace1, trace2];
var layout = {
  bargap: 0.05,
  bargroupgap: 0.2,
  barmode: "overlay",
  title: {
    text: "Sampled Results"
  },
  xaxis: {
      title: {
          text: "Value"
      }
  },
  yaxis: {
      title: {
          text: "Count"
      }
  }
};
Plotly.newPlot('myDiv', data, layout);

Cumulative Histogram

var x = [];
for (var i = 0; i < 500; i ++) {
	x[i] = Math.random();
}

var trace = {
    x: x,
    type: 'histogram',
	cumulative: {enabled: true}
  };
var data = [trace];
Plotly.newPlot('myDiv', data);

Normalized Histogram

var x = [];
for (var i = 0; i < 500; i ++) {
	x[i] = Math.random();
}

var data = [
  {
    x: x,
    type: 'histogram',
	histnorm: 'probability',
	marker: {
        color: 'rgb(255,255,100)',
     },
  }
];
Plotly.newPlot('myDiv', data);

Specify Binning Function

var x = ["Apples","Apples","Apples","Oranges", "Bananas"]
var y = ["5","10","3","10","5"]

var data = [
  {
    histfunc: "count",
    y: y,
    x: x,
    type: "histogram",
    name: "count"
  },
  {
    histfunc: "sum",
    y: y,
    x: x,
    type: "histogram",
    name: "sum"
  }
]

Plotly.newPlot('myDiv', data)