[...document.querySelectorAll(el)] code example

Example 1: js queryselectorall

var container = document.querySelector("#test");
var matches = container.querySelectorAll("div.highlighted > p");

Example 2: js querySelectorAll

// https://www.google.com/
// this puts a border around the 'a' tags of 'Google offered in' section.

// within this id find all the 'a' tags
var languages = document.querySelectorAll("#SIvCob a");


// loop through all the a tags a add a border to the tags
for(var i = 0; i < languages.length; i++){
    document.querySelectorAll("#SIvCob a")[i].style.border = "1px solid black";

}