Absolutely no javascript/jQuery or any other script, this menu uses just css to produce a multi level tree style menu with slide action, suitable for all the latest browsers and operating systems.
This is the previous menu moved back to the right of the screen and solves the problem of having a double scrollbar when the menu the expanded menu is longer than the browser height.
This version uses 'flexbox' to center the menu vertically and has a panel to the left of the menu which can be used for any information you like.
To open the menu click/tap the three bar icon at the top right of the page. The menu will always be shown in the start position with all sub menus closed.
To open a sub menu just click/tap an item with the down arrow to the left, and to close the same sub menu click/tap the same list item or click/tap another branch of the menu.
The menu will stay vertically aligned until it becomes too high for screen and requires scrolling to see all the items.
To close the menu click/tap the 'cross' at the top right of the screen, this will close any open sub menus before closing the menu.