how to attach attribute to html code example

Example 1: javascript create element with attributes

var element = document.createElement("span");
element.setAttribute("style", "color: red");
document.body.appendChild(element);

Example 2: js setattribute

const link = document.querySelector('a');

console.log(link.getAttribute('href'));
link.setAttribute('href', 'https://yandex.ru');
link.innerText = 'The Next Link';

const mssg = document.querySelector('p');

console.log(mssg.getAttribute('class'));

mssg.setAttribute('class', 'success');
mssg.setAttribute('style', 'color: green;');