(function() {
  var debounce = function(func, delay) {
    var inDebounce;
    return function() {
      var context = this;
      var args = arguments;
      clearTimeout(inDebounce);
      inDebounce = setTimeout(function() {
        func.apply(context, args);
      }, delay);
    }
  }
  var scrollHeight = document.documentElement.scrollHeight - window.innerHeight;
  var quarterHeight = scrollHeight / 4;
  var quarters = 0;
  var scrollDistance, divisible, percent;
  document.addEventListener("scroll", debounce(function() {
    scrollDistance = window.pageYOffset || (document.documentElement || document.body.parentNode || document.body).scrollTop;
    divisible = Math.trunc(scrollDistance / quarterHeight);
    if (quarters < divisible) {
      scrollPercent = divisible * 25;
      heap.track('Scroll Depth', {
        percent: scrollPercent
      });
      quarters++;
    }
  }, 100));
}());