JSFiddle - React, Tailwind, and code Playground

HTML

<p>Lorem Ipsum</p>
<p class="middle">Lorem Ipsum</p>
<p class="middle">Lorem Ipsum</p>
<p>Lorem Ipsum</p>

JavaScript

function filter(tagName,classe){
    var aryP = document.getElementsByTagName(tagName);
    var len  = aryP.length;
    var aryPMiddle = [];
    for (var i=0;i < len; i++){
        if (aryP[i].getAttribute('class') == classe){
          aryPMiddle.push(aryP[i]);
        }
    }
    console.log(aryPMiddle);
}
filter('p','middle');