JSFiddle - React, Tailwind, and code Playground

HTML

<p>Крутите вниз</p>

CSS

BODY {
    margin:0;
    padding:0;
    }
P {
    padding:9px;
    font:19px sans-serif;
    }
DIV {
    height:1px;
    overflow:hidden;
    background:#888;
    }

JavaScript

for(var i=0; i<=1000; i++) {
    var div = document.createElement('div');
        div.style.width = i/10 + '%'
    document.body.appendChild(div);
}