CSS3 :nth-child() Selector
Specify a background color for every <p> element that is the second child of its parent:
More "Try it Yourself" examples below.
Definition and Usage
The :nth-child(n) selector matches every element that is the nth child, regardless of type, of its parent.
n can be a number, a keyword, or a formula.
Tip: Look at the :nth-of-type() selector to select the element that is the nth child, of a particular type, of its parent.
The numbers in the table specifies the first browser version that fully supports the selector.
Odd and even are keywords that can be used to match child elements whose index is odd or even (the index of the first child is 1).
Here, we specify two different background colors for odd and even p elements:
Using a formula (an + b). Description: a represents a cycle size, n is a counter (starts at 0), and b is an offset value.
Here, we specify a background color for all p elements whose index is a multiple of 3: