JS Add or replace content on one or several HTML elements using a CSS selector

jsaddcontent.js

document.querySelector('.haiku').innerText = ('This is a Haiku')
// This will replace the content inside the first element that matches that CSS selector.
 
document.querySelectorAll('.haiku')[2].innerText = ('This is a Haiku')
// This will add a (.haiku) to the third element that matches that CSS selector.
 
document.querySelectorAll('.haiku').forEach(function(i){i.innerText = ('This is a Haiku')})
// This will replace the content of all elements that match that CSS selector

//There are ways to add content before and after the existing content instead of replacing it
// append to the element's content
el.innerHTML += '<p&gt;Hello World!</p&gt;';

// prepend to the element's content
el.innerHTML = '<p&gt;Hello World!</p&gt;' + el.innerHTML;