JSFiddle - React, Tailwind, and code Playground

HTML

<a my_own_attr='123' id='x'>123</a>
<a my bad attr='456' id='y'>123</a>

JavaScript

var x = document.getElementById("x").getAttribute("my_own_attr");
alert(x);
var y = document.getElementById("y").getAttribute("my bad attr");
alert(y);