Scroll down an infinite scroll page each 5 seconds, stop if bottom reached.

infinite-scroll-down.js

(function() {
  var interval = 2000;
  var failLimit = 20;
  var stopped = 0;
  var tick = setInterval(function() {
    var ph = document.body.clientHeight;
    var top = window.pageYOffset;
    var ih = window.innerHeight;

    if (ph > top + ih) {
      window.scrollTo(0, ph);
      console.log('scrolling');
    } else {
      stopped++;
      console.log('Failed scrolling ' + stopped + ' times, trying again in ' + interval/1000 + ' seconds...');
      if (stopped >= failLimit) {
        console.log('Scroll fail limit of ' + failLimit + ' has happened, stopping loop.');
        alert('Page end reached!');
        clearInterval(tick);
      }
      
    }
  }, interval);
})()