Dropdowns are toggleable, contextual overlays for displaying lists of links and more. They’re made interactive with the included Bootstrap dropdown JavaScript plugin.
                                        You can optionally use <button> elements in your dropdowns instead of <a>s.
                                    
Add a header to label sections of actions in any dropdown menu.
Separate groups of related menu items with a divider.
                                        Add .disabled to items in the dropdown to style them as disabled.