Detect browser capabilities reliably with JS

detect-browser-skills.js

document.addEventListener("DOMContentLoaded", function () {
  var touchDetect = function () {
    document.documentElement.classList.add("has-touch");
    document.removeEventListener("touchstart", touchDetect);
  };
  var hoverDetect = function () {
    document.documentElement.classList.add("has-hover");
    document.removeEventListener("mouseenter", hoverDetect);
  };

  document.addEventListener("touchstart", touchDetect);
  document.addEventListener("mouseenter", hoverDetect);
});