jquery - Javascript loop for every 2 classes -

hi i've got small issue not sure how solve javascript/jquery. ive got several div classes want create loop add class on divs, without having add id on them manually add id or class through javascript code.

heres idea of mean:

<div></div><div></div>     <div></div><div></div> <div></div><div></div>     <div></div><div></div> 

this have lets 2 divs row. want a class added in way make this:

<div class="green"></div>           <div></div>     <div></div>                         <div class="green"></div> <div class="green"></div>           <div></div>     <div></div>                         <div class="green"></div> 

so guessing sort of loop every 2 divs repeat in reverse.

basically want zig-zag.

there no need of loops. can use :nth-child selector follow:

$('div:nth-child(4n+1)').addclass('green'); // selects 1, 5, 9, 13, ... $('div:nth-child(4n)').addclass('green'); // selects 4, 8, 12, 16, ... 

demo

here pure css demo.

body {    width: 120px;  }  div {    height: 50px;    width: 50px;    background: red;    margin: 5px;    float: left;  }  div:nth-child(4n+1) {    background: green;  }  div:nth-child(4n) {    background: green;  }

<div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>  <div></div>