Even in the world of jQuery... promises rain supreme.. even if its a bastardized.

jqpromises.js

$(".feature-tab-header").on("click", function() {
  var targetTab = "." + $(this).attr("id");
  var targetHeader = this;
  var promises = [
    $(".feature-tab.active").removeClass("active").promise(),
    $(".feature-tab-header").removeClass("active").promise()
  ];
  return $.when(promises).done(function() {
    $(targetHeader).addClass("active");
    $(targetTab).addClass("active");
  });
});