JSFiddle - React, Tailwind, and code Playground

HTML

<div class='item'>
    <h1 id="Python">Python</h1>
</div>

<div class='item'>
    <h1 id="C++">C++</h1>
</div>

<div class='item'>
    <h1 id="PHP">PHP</h1>
</div>

JavaScript

var myList = document.getElementsByTagName('h1');
var languages = [].slice.call( myList ).map( function( item ){
    return item.innerHTML;
});

console.log( languages );