How to change the bootstrap caret pointing direction on click event

Question

I'm using 2.3.2 bootstrap

As I can change the position of the caret icon when I click the menu button.

I need that when I click the icon caret pointing up and when you click on another item the caret back to the initial state.

How is this possible?

The nav code

<div id="navi">
    <div class="container">
      <nav>
        <div class="navbar">
          <div class="navbar-inner">
            <div class="row">
              <button type="button" class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
              </button>

              <div class="span2">
                <a class="brand" href="#"></a>
              </div>

              <div class="span10">
                <div class="nav-collapse collapse">
                  <div class="row">
                    <div class="span8">
                      <ul class="nav">
                        <li class="dropdown">
                          <a href="#" class="dropdown-toggle" data-toggle="dropdown">Lorem 3 opes<b class="caret"></b></i></a>
                          <ul class="dropdown-menu">
                            <li><a href="#">Lorem</a></li>
                            <li><a href="institucional.html">Olosmpa</a></li>
                            <li><a href="#">Lorem 2 isum</a></li>

                          </ul>
                        </li>

                        <li class="dropdown">
                          <a href="#" class="dropdown-toggle" data-toggle="dropdown">Lorem mas<b class="caret"></b></a>
                          <ul class="dropdown-menu">
                            <li><a href="#">Lorem</a></li>
                            <li><a href="institucional.html">Olosmpa</a></li>
                            <li><a href="#">Lorem 2 isum</a></li>

                          </ul>
                        </li>



                      </ul> 
                    </div><!-- /span8 -->

                    <div class="span2">
                      <div>
                        <form id="buscar-fixed" class="navbar-form form-search">
                          <div class="input-append">
                            <input class="inputBusqueda span2" type="text" placeholder="Buscar..." />
                            <button class="btn" type="button"><i class="icon-search icon-white"></i></button>


                          </div>
                        </form>

                      </div>
                    </div><!-- /span2 -->
                  </div><!-- /row -->
                </div><!--/.nav-collapse -->
              </div><!-- /span10 -->
            </div><!-- /row -->
          </div><!-- /nav-inner -->
        </div><!-- /navbar -->
      </nav>
    </div><!-- /container -->
  </div><!-- fin #nav-sup -->

Link to fiddle to try to resolve

Image example of the problem

Answer 1

you can add this

.nav .dropdown.open .caret{
    border-top: none;
    border-bottom: 4px solid #000000;
}

Updated Fiddle