A comparison between two common techniques for drawing halos to make labels readable regardless of the background color.
The first technique creates two SVG <text> elements one upon each other. The one in the background has a white stroke, while the one in the foreground has a black fill.
The second technique declares a combination of CSS text-shadows on a single text.
Modified http://d3js.org/d3.v3.min.js to a secure url
https://d3js.org/d3.v3.min.js