これはあなたのためにそれを行う必要があります。コードは以下のようにコメントされています。
$(window).on('scroll', function(){
// with '.my-class'
$('.my-class').removeClass('active')
// who's beginning Y position is greater than current Y position
.filter(function(){
return $(this).offset().top > $(window).scrollTop();
}).first()
// find the next div
.next()
// do stuff
.addClass('active');
}).trigger('scroll');
body {background: #fff;}
.my-class {
padding: 2em;
border: 1px solid #eee;
margin: 1em;
border-radius: 1em;
}
.my-class.active {
border-color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
<div class="my-class">Test</div>
http://stackoverflow.com/questions/3942776/using-jquery-to-find-an-element-at-a-particular-position – InferOn