CSS :nth-child() Selector

Last Updated : 02 Nov, 2021

The :nth-child() CSS pseudo-class selector is used to match the elements based on their position in a group of siblings. It matches every element that is the nth-child, regardless of the type, of its parent.

Syntax:

:nth-child(number) {
    // CSS Property
}

Where number is the single argument that represents the pattern for matching elements. It can be odd, even, or in a functional notation.

odd: It represents elements whose position is odd in a series: 1, 3, 5, etc.
even: It represents the elements whose position is even in a series: 2, 4, 6, etc.
functional notation (<An+B>): It represents elements whose position of siblings matches the pattern An+B, for every positive integer or zero value of n. Here, A represents the integer step size, B represents the integer offset.

Example 1: In this example, every odd paragraph is selected. Formula used is 2n+1 i.e 1, 3, 5, etc paragraphs are selected.

HTML

<!DOCTYPE html>
<html>
  
<head>
    <title>CSS :nth-child Selector</title>
    <style>
    p:nth-child(2n+1) {
        background: green;
        color: white;
    }
    </style>
</head>
  
<body style="text-align:center">
    <h1 style="color:green;">
            GeeksforGeeks
        </h1>
    <h2>
            CSS :nth-child Selector
        </h2>
    <p>A computer science portal for geeks.</p>
  
    <p>Geeks classes an extensive classroom programme.</p>
  
</body>
  
</html>

Output:

nthchild

Example 2: In this example, every even <li> is selected i.e. 2, 4, 6, etc.

HTML

<!DOCTYPE html>
<html>
  
<head>
    <title>CSS :nth-child Selector</title>
    <style>
    li {
        width: 30%;
    }
      
    li:nth-child(even) {
        background: green;
        color: white;
    }
    </style>
</head>
  
<body style="text-align:center">
    <h2>
            CSS :nth-child Selector
        </h2>
      
<p>Sorting Algorithms</p>
  
    <ul>
        <li>Quick sort.</li>
        <li>Merge sort.</li>
        <li>Insertion sort.</li>
        <li>Selection sort.</li>
    </ul>
</body>
  
</html>