When working with an HTML page, the attributes that you need depend on the plugins that you’re using.
Used when submitting a post.
Used by Jquery to find an element when doing a $(#id_name).
Used by CSS. Prefixed by (#)
Used by CSS. Prefixed by (.)
I didn’t cover all of the cases, since I jotted down what I remembered, but it is a good idea to create a table for this stuff.