How to create a html button

hey guys what im trying to accomplish is a button like pinterest.com
on top left ( the categories button).
how can I do that.
Les says I already have my categories

HTML:

<li>cat1</li>

<li>cat2</li>

<li>cat3</li>

<li>cat4</li>

and onclick of he button display that categories

thank you in advance

See original post by bondigor69