А вообще это на одном CSS делается
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="style.css">
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
#cont {
position: relative;
display: flex;
flex-direction: column;
width: 100%;
height: 100vh;
overflow-y: scroll;
scroll-snap-type: y mandatory;
}
section {
position: relative;
width: 100%;
min-height: 100vh;
font-size: 60px;
color: #FFF;
scroll-snap-align: start;
}
.one {
background-color: tomato;
}
.two {
background-color: gold;
}
.three {
background-color: green;
}
.four {
background-color: blue;
}
</style>
<title>Document</title>
</head>
<body>
<div id=cont>
<section class="one">1111</section>
<section class="two">2222</section>
<section class="three">3333</section>
<section class="four">4444</section>
</div>
</body>
</html>