How to add a class to all blocks that are displayed after the 3rd block?

Question

JavaScript

How to add a class to all blocks that are displayed after the 3rd block?
for example , after the 3rd block, the green class should be substituted for all the rest

Answer 1

If parent is common:

document
  .querySelectorAll('.service:nth-child(n + 5)')
  .forEach(n => n.classList.add('green'));

Otherwise:

Array
  .from(document.querySelectorAll('.service'))
  .slice(4)
  .forEach(n => n.classList.add('green'));

Answer 2

You can simply style:

.container div:nth-child(n + 4){
  border:1px solid green;
  background-color:lightgreen;
}

spoiler