Udacity jQuery Webcast: When Does Sizzle Get Used?

sizzle.js

$(document).ready(function() {
    // Sizzle is jQuery's internal library for DOM element selection. When does it actually get used?
    
    // modern browser, i.e. Chrome, Firefox, Safari, IE 8+, Edge
    
    $("#title"); // Nope! --> document.getElementById("title");
    
    $(".my-class") // Nope! --> document.getElementsByClassName("my-class");
    
    $("body > div.foo #element"); // Nope! --> document.querySelectorAll("body > div.foo #element");
    
    // IE 6,7 and other outdated browsers
    
    $("#title"); // Nope! --> document.getElementById("title");
    
    $(".my-class") // Nope! --> document.getElementsByClassName("my-class");
    
    $("body > div.foo #element"); // Yes! Here, we need Sizzle, since we don't have the querySelectorAll function.
});