即使鼠标悬停丢失，下拉菜单仍然可见

I need to have main menu with dropdown menu items. So, when user hovers menu item then dropdown menu is shown. This is already done by CSS and :hover selector. However, usually when :hover is lost (mouse is moved outside menu item element) then appropriate dropodown also disappears. But what I need - menu is still seen and disappears only on click.I need to have main menu with dropdown menu ite