I wonder if it’s worth detecting the vendor prefix globally, rather than making it specific to d3_selection_style. Then you might be able to shorten some other vendor-specific checks, e.g.,

```js
var d3_timer_frame = d3_window.requestAnimationFrame
    || d3_window[d3_vendor + "RequestAnimationFrame"]
    || function(callback) { setTimeout(callback, 17); };
```