d3.js in Node.js

index.js

/**
 * > npm install d3
 */

// In Node.js, d3.js works in a virtual document provided by jsdom.
var d3 = require('d3');

//--------

// Create the SVG element.
var svg = d3.select('body').append('svg')

  // This attributes are required to form a valid SVG document .
  .attr('xmlns', 'http://www.w3.org/2000/svg')
  .attr('version', '1.1')
  
  // Defines the viewPort (displayed area) of the document.
  .attr('width', '800px')
  .attr('height', '600px')
;


// Do whatever manipulation you want here.
// ...
// ...


// If you want to include inline CSS.
svg.append('defs').append('style')
  .attr('type', 'text/css')
  .text([
    '<![CDATA[',
    'path { stroke: black; }',
    ']]>'
  ].join('\n'))
;

// Extract the code from the code and preprend the doctype.
var svgContent = [
  '<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"',
  ' "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">',
  svg.remove().node().outerHTML
].join('');


// Prepend the XML header.
svgContent = [
  '<?xml version="1.0" standalone="no"?>',
  
  // If you want to add an external stylesheet.
  '<?xml-stylesheet href="mystyle.css" type="text/css"?>',
  
  svgContent
].join('');