https://railsguides.jp/railsguides/javascripts/guides.js

1$.fn.selectGuide = function(guide) {
2  $("select", this).val(guide);
3};
4
5var guidesIndex = {
6  bind: function() {
7    var currentGuidePath = window.location.pathname;
8    var currentGuide = currentGuidePath.substring(currentGuidePath.lastIndexOf("/")+1);
9    $(".guides-index-small").
10      on("change", "select", guidesIndex.navigate).
11      selectGuide(currentGuide);
12    $(document).on("click", ".more-info-button", function(e){
13      e.stopPropagation();
14      if ($(".more-info-links").is(":visible")) {
15        $(".more-info-links").addClass("s-hidden").unwrap();
16      } else {
17        $(".more-info-links").wrap("<div class='more-info-container'></div>").removeClass("s-hidden");
18      }
19    });
20    $("#guidesMenu").on("click", function(e) {
21      $("#guides").toggle();
22      return false;
23    });
24    $(document).on("click", function(e){
25      e.stopPropagation();
26      var $button = $(".more-info-button");
27      var element;
28
29      // Cross browser find the element that had the event
30      if (e.target) element = e.target;
31      else if (e.srcElement) element = e.srcElement;
32
33      // Defeat the older Safari bug:
34      // http://www.quirksmode.org/js/events_properties.html
35      if (element.nodeType === 3) element = element.parentNode;
36
37      var $element = $(element);
38
39      var $container = $element.parents(".more-info-container");
40
41      // We've captured a click outside the popup
42      if($container.length === 0){
43        $container = $button.next(".more-info-container");
44        $container.find(".more-info-links").addClass("s-hidden").unwrap();
45      }
46    });
47  },
48  navigate: function(e){
49    var $list = $(e.target);
50    var url = $list.val();
51    window.location = url;
52  }
53};