I have got a responsive joomla page with bootstrap. When I click on the button for the mobile menu (class="navbar-toggle") I would like to extend it and show the li-element (".item-259") which contains a dropdown-menu already opened, by adding the class "open".

I don't know why this code isn't working, but the class "open" is not added to li.item-259, when I click on the button and it shows the menu...

Does anybody know what's wrong with it?

Edit: that is the html... thanks for your fast help

It is so weird... this also isn't working:

BUT this is working:

Problem with that is, that my submenu opens on every click on the document (everywhere) if it is not the mobile version...