jQuery vs. Vanilla JavaScript

Selecting elements

$('#el')
$('.card')
$('ul li')

document.querySelector('#el')
document.querySelectorAll('.card')
document.querySelectorAll('ul li')

DOM Loaded

$(document).ready(function() {
  // Handler
});

$(function() {
  // Handler
});

window.onload = function() {
  // Handler
}

window.addEventListener("load", function() {
  // Handler
});

Attention: executes immediately, not on page load!

(function () {
  // Handler
})();

Event Handler

function handler() {
  $(this)
}

function handler() {
  this
}