I've created a custom CSS drop-down menu that works well, but I've realized that updating this menu across all the HTML pages on my website would be a tedious task. If I ever need to add a new section and tier to the menu, I'd have to update numerous HTML files for just one line of code.
Is there a way to write this menu once on the main page and call it on all other HTML pages?
I've tried experimenting with Objects, Iframes, and calling the dropdown menu from a separate HTML file, but encountered issues like scroll bars appearing when the menu expands or the methods embedding into the page, rather than having the content behind the drop-down menu as it currently does.
Here is an unedited page for reference:
And here is a test page where the issue arises:
As you can see, the top image is obscured and the submenus don't fly out completely. How can I fix this?
I'm quite new to this, so any help would be greatly appreciated.