website/static/playground.js/getOptions
function getOptions() {
  var options = {};
  OPTIONS.forEach(function(option) {
    var elem = document.getElementById(option);
    if (elem.tagName === "SELECT") {
      options[option] = elem.value;
    } else if (elem.type === "number") {
      options[option] = Number(elem.value);
    } else {
      var isInverted = elem.hasAttribute("data-inverted");
      options[option] = isInverted ? !elem.checked : elem.checked;
    }
  });
  return options;
}