[Sticky element JS]

sticky.js

var sticky = function(elementSelector, heightSelector){
		var h = document.querySelector(elementSelector);
		var stuck = false;
		var stickPoint = getDistance(heightSelector);


		function getDistance(heightSelector) {
			var topDist = h.offsetTop || document.querySelector(heightSelector).offsetHeight;
			return topDist;
		}

		window.onscroll = function(e) {
			var distance = getDistance(heightSelector) - window.pageYOffset;
			var offset = window.pageYOffset;
			if ( (distance <= 0) && !stuck) {
				h.classList.add('sticky');
				document.body.classList.add('sticky-elements');
				stuck = true;
			} else if (stuck && (offset <= stickPoint)){
				h.classList.remove('sticky');
				document.body.classList.remove('sticky-elements');
				stuck = false;
			}
		}
	};