Category Drop Down Menu (JavaScript)

Im Wondering how possible (if at all) if i could make a drop down menu from my page links at the top of my blog, to list the catagories from my blog…

here is my blog to help make things easier…

https://www.rivercitylife.org.au/blog/index.php

Now i am aiming to make a drop down menu, say with javascript, as this has worked before. I would want it dropping down from where it says ‘Home’ at the top of the page…

Anyone have any ideas? I’m not sure about how to go about it exactly…

Here is an example of exactly the type of layout i am looking for..

https://webhost.bridgew.edu/etribou/layouts/Tank!/index.html

Thanks!

-Crawf