Create a download link for an svg client side (Like one drawn from D3.js) (Excuse the jQuery, this could easily be done in raw js)

javascript_svg_download.js

  $('.container svg').attr({
    'xmlns': 'http://www.w3.org/2000/svg',
    'xmlns:xlink': "http://www.w3.org/1999/xlink"
  });

  var base64SvgText = btoa(
    encodeURIComponent(
      $('.container').html()
    ).replace(/%([0-9A-F]{2})/g,
      function (match, p1) {
        return String.fromCharCode('0x' + p1);
      }
    )
  );

  $('a.download-svg').attr({
    'download': 'cool-graph.svg',
    'href': 'data:image/svg+xml;charset=utf-8;base64,' + base64SvgText
  });