https://egzamin-informatyk.pl/assets/js/scroll-banner.js

1window.onload = (event) => {
2	
3var rekl_start = document.querySelector("#sidead");	
4var viewportOffset = rekl_start.getBoundingClientRect();
5var rekl_startTop1 = viewportOffset.top;
6var lastKnownScrollPosition = window.scrollY;
7var rekl_startTop = 0;
8if (rekl_startTop1<0) rekl_startTop = lastKnownScrollPosition - Math.abs(rekl_startTop1);
9else rekl_startTop = lastKnownScrollPosition + rekl_startTop1;
10var rekl_height = viewportOffset.height;
11if (rekl_height < 10) rekl_height = 620;
12var koniec = document.querySelector("#siteend");	
13var viewportOffsetkoniec = koniec.getBoundingClientRect();
14var koniecTop1 = viewportOffsetkoniec.top;
15var koniecTop = 1000;
16if (koniecTop1<0) koniecTop = lastKnownScrollPosition - Math.abs(koniecTop1);
17else koniecTop = lastKnownScrollPosition + koniecTop1;
18var topPadding = 50;
19var sideb = document.querySelector("#side");
20var sideOffset = sideb.getBoundingClientRect();
21var poczatekside1 = sideOffset.top;
22if (poczatekside1<0) poczatekside = lastKnownScrollPosition - Math.abs(poczatekside1);
23else poczatekside = lastKnownScrollPosition + poczatekside1;
24		
25document.addEventListener("scroll", (event) => {
26
27	viewportOffsetkoniec = koniec.getBoundingClientRect();
28	koniecTop1 = viewportOffsetkoniec.top;
29	koniecTop = lastKnownScrollPosition + koniecTop1;
30	
31	lastKnownScrollPosition = window.scrollY;
32	var rekl = document.querySelector("#sidead");	
33	
34	if (lastKnownScrollPosition < rekl_startTop - topPadding) {
35		rekl.style.top = "0px";
36	} 
37	else if (lastKnownScrollPosition > rekl_startTop - topPadding && lastKnownScrollPosition < koniecTop - rekl_height - 400) {
38		newpos = lastKnownScrollPosition - rekl_startTop + topPadding;
39		rekl.style.top = Math.floor(newpos) + "px";
40	}
41
42});
43};