JSFiddle - React, Tailwind, and code Playground

HTML

<div>
   <br><br><br><br><br><br><br><br><br><br><br><br><br><br> 
   <br><br><br><br><br><br><br><br><br><br><br><br><br><br> 
   <span>Hello !!</span>
   <br><br><br><br><br><br><br><br><br><br><br><br><br><br>
   <br><br><br><br><br><br><br><br><br><br><br><br><br><br>
</div>

CSS

div {
    width:200px;
    height:200px;
    overflow:scroll;
}

span {
    font:bold 15px Arial;
    background:#000;
    color:#0099f9;
}

JavaScript

$(document).ready(function() {
         $('div').scroll(function() {
             var pos    = $('div').scrollTop();
             var offset = $('span').offset().top;
             if(pos >= offset ) {
               alert('you have reached your destiny');
             }
       });
    });