get tabs working in ie9

docs/javascript.html

@@ -486,7 +486,7 @@ $('a[data-toggle="tab"]').on('shown', function (e) {
             <li><a href="#messages" data-toggle="tab">Messages</a></li>
             <li><a href="#settings" data-toggle="tab">Settings</a></li>
             <li class="dropdown">
-              <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a>
+              <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown <b class="caret"></b></a>
               <ul class="dropdown-menu">
                 <li><a href="#dropdown1" data-toggle="tab">@fat</a></li>
                 <li><a href="#dropdown2" data-toggle="tab">@mdo</a></li>