JSFiddle - React, Tailwind, and code Playground

HTML

<div id="szlider">
    <div id="szliderbar">
    </div>
    <div id="szazalek">
    </div>
</div>

CSS

#szlider{
    width:100%;
    height:35px;
    border:1px solid #000;
    background-color: #ddd;
    overflow:hidden; 
}
#szliderbar{
    width:37%;
    height:35px;
    border-right: 1px solid #000000;
    background: #d65946; 
}
#szazalek {
    color: #FFF;
    font-size: 25px;
    font-style: italic;
    font-weight: bold;
    left: 25px;
    position: relative;
    top: -31px;
}

JavaScript

function drawszlider(ossz, meik){
    var szazalek=Math.round((meik*100)/ossz);
    document.getElementById("szliderbar").style.width=szazalek+'%';
    document.getElementById("szazalek").innerHTML=szazalek+'%';
}
drawszlider(121, 56);