https://180engineering.com/wp-content/themes/180engineering/js/timeline.js?ver=1790598529

1(function(){
2	function VerticalTimeline( element ) {
3		this.element = element;
4		this.blocks = this.element.getElementsByClassName("journey-timeline__block");
5		this.images = this.element.getElementsByClassName("journey-timeline__item-number");
6		this.contents = this.element.getElementsByClassName("journey-timeline__content");
7		this.offset = 0.8;
8		this.hideBlocks();
9	};
10
11	VerticalTimeline.prototype.hideBlocks = function() {
12		if ( !"classList" in document.documentElement ) {
13			return; // no animation on older browsers
14		}
15		//hide timeline blocks which are outside the viewport
16		var self = this;
17		for( var i = 0; i < this.blocks.length; i++) {
18			(function(i){
19				if( self.blocks[i].getBoundingClientRect().top > window.innerHeight*self.offset ) {
20					self.images[i].classList.add("journey-timeline__item-number--hidden"); 
21					self.contents[i].classList.add("journey-timeline__content--hidden"); 
22				}
23			})(i);
24		}
25	};
26
27	VerticalTimeline.prototype.showBlocks = function() {
28		if ( ! "classList" in document.documentElement ) {
29			return;
30		}
31		var self = this;
32		for( var i = 0; i < this.blocks.length; i++) {
33			(function(i){
34				if( self.contents[i].classList.contains("journey-timeline__content--hidden") && self.blocks[i].getBoundingClientRect().top <= window.innerHeight*self.offset ) {
35					// add bounce-in animation
36					self.images[i].classList.add("journey-timeline__item-number--bounce-in");
37					self.contents[i].classList.add("journey-timeline__content--bounce-in");
38					self.images[i].classList.remove("journey-timeline__item-number--hidden");
39					self.contents[i].classList.remove("journey-timeline__content--hidden");
40				}
41			})(i);
42		}
43	};
44
45	var verticalTimelines = document.getElementsByClassName("journey-timeline"),
46		verticalTimelinesArray = [],
47		scrolling = false;
48	if( verticalTimelines.length > 0 ) {
49		for( var i = 0; i < verticalTimelines.length; i++) {
50			(function(i){
51				verticalTimelinesArray.push(new VerticalTimeline(verticalTimelines[i]));
52			})(i);
53		}
54
55		//show timeline blocks on scrolling
56		window.addEventListener("scroll", function(event) {
57			if( !scrolling ) {
58				scrolling = true;
59				(!window.requestAnimationFrame) ? setTimeout(checkTimelineScroll, 250) : window.requestAnimationFrame(checkTimelineScroll);
60			}
61		});
62	}
63
64	function checkTimelineScroll() {
65		verticalTimelinesArray.forEach(function(timeline){
66			timeline.showBlocks();
67		});
68		scrolling = false;
69	};
70})();