Hehe, I finally find out how to pop up something without window frame.
Here are the examples of a normal window pop up & a div pop up which I want to implement soon.
https://gist.github.com/fabiolee/de73a89b49590ebf468aeb92d518f736.js
Both example can be run when the code paste in a html extension file. This is what I called “Div Pop Up”.