JSFiddle - React, Tailwind, and code Playground

HTML

<span id="val">1</span>
<div id="dummy"></div>

CSS

#dummy { display:none; }

JavaScript

var a = 1;
$(function(){
    $('#dummy').animate({'height':'100px'},{
        duration: 5000, 
        step: function(now,fx){ 
            $('span').text(now/100*9+1);
        }
    });
});