Automatically counting and numbering HTML elements with CSS counters

Say you had an unknown number of <div> elements and (for some reason) you wanted to count them and number each other them automatically - how would you do it? If you're like me, your first thought would be to use some kind of Javascript to play around with the DOM. What if I told you (insert Morpheus voice here) you can do it with CSS?

How to use CSS counters

Getting counters working requires three steps:

• Initialize the counter with counter-reset
• Increment the counter with counter-increment
• Show the current counter value with counter()

It's pretty simple, really. The Pen below demonstrates how to count and number three <div> elements.

Where would this be useful?

I discovered CSS counters while looking for a way to number images on my blog posts. That's one place it would really come in handy. Here's a quick example: