Selector Type Efficiency There are four main types of selectors in CSS–ID, class, tag and universal. IDs are unique elements denoted by the hash, like our old friend #current.

Note that we used the width and height attributes to specify a size for the image element in this simple example. In the real world, once we’ve done more on our quest to learn HTML and CSS, we ...

Listing 1. Using the :has pseudo-class (example 1) div:has (span) That’s pretty useful already, as a way to select elements up the selector chain, but there is more.

I recommend learning id, class name and HTML tag selectors first. The id selector matches HTML elements with the same id. It's often used when you want to locate a specific element in the Document ...