The CSS2.1 spec introduced a new technique allowing developers to combine three CSS properties and a pseudo-element to create auto-incrementing counters — similar to what is displayed in an ordered list.

While counters for lists are limited to <ol> or <ul> elements and only with simple incrementation, the new counter method introduced in CSS2.1 allows for integers to be prepended to any set of elements, and is quite flexible.

This technique is a bit confusing because it uses multiple CSS properties, and looks different than most CSS code. I hope to clarify how it’s used and I’ll run down some possible ways it can be implemented, along with some benefits and drawbacks.