Throttled scroll trigger

var scheduled = false,
    _throttleDelay = 200;

function ScrollHandler(e) {
  //throttle event:
  if (!scheduled) {
    scheduled = true;
    setTimeout(function () {
      console.log('scroll');

      //do work
      if ($(window).scrollTop() + $(window).height() > $(document).height() - 100) {
          alert("near bottom!");
      }
    
      // Allow method to run again when user scrolls next time.
      scheduled = false;
    }, _throttleDelay);
  }
}