Small YUI demo

<!DOCTYPE html>
<html>

  <head>
    <script data-require="yui@*" data-semver="3.3.0" src="//cdnjs.cloudflare.com/ajax/libs/yui/3.3.0/yui-min.js"></script>
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
  </head>

  <body>
    <input type="button" id="btn1" value="Click"/>
  </body>

</html>

YUI().use('node', 'event', 'console', function (Y) {
    // The Node and Event modules are loaded and ready to use.
    var button = Y.one("#btn1").on("click", onClick);

    function onClick() {
      alert("Clicked from YUI!");
    }
});