Using jQuery lets you create specific selectors based on tag names and classes, but this approach necessitates several iterations as jQuery loops through DOM elements to find a match. You can speed up the DOM by using the document.getElementById() method instead.
// With jQuery
var button = jQuery('body div.window > div.minimize-button:nth-child(3)')[0];
// With document.getElementById()
var button = document.getElementById('window-minimize-button');