Adding class as per LI postion [duplicate]

Question

I have below markup,

<ul>
<li>1</li> //light BG
<li>2</li>
<li>3</li>
<li>4</li> //light BG
<li>5</li>
<li>6</li>
......
</ul>

I want to add class dark and light, as per position of li.

• First li should be light
• 2nd,3rd should be dark
• 4th, 5th should be light
• same pattern....

Answer 1

$('ul li:nth-child(3n-2)').addClass('light');

$('ul li::not(:nth-child(3n-2))').addClass('dark');

DEMO