Javascript/JQuery :-
HTML :-
<< How to Add this >>
Step 1:- Open Dashboard and Click on "Template"
Step 2:- Click on "Edit HTML"
Step 3:- Click on "Proceed"
Step 4:- Press CTRL + F and type body
Step 5:- Paste The Javascript/JQuery from above just before the body Tag
Step 6:- Click on "Save Template"
Step 7:- Add HTML code from above in your body Tag where you want this menu to appear and Click on "Save Template"
Step 8:- After Saving Template, Click on "Close"
Step 9:- Now, Click on "Layout"
Step 10:- Click on "Add a Gadget"
Step 11:- Add "HTML/Javascript" Gadget to your Blog
Step 12:- Copy and Paste the above CSS in Content Area
Step 13:- Click on "Save" and You're Done.