title: querySelector vs. getElementById
body: <p>I have heard that <code>querySelector</code> and <code>querySelectorAll</code> are new methods to select DOM elements. How do they compare to the older methods, <code>getElementById</code> and <code>getElementsByClassName</code> in terms of performance and browser support?</p>
  <p>How does the performance compare to using jQuery's query selector?</p>
  <p>Is there a best practice recommendation for which method to use?</p>