<div id="container">
   <div></div>
   <div></div>
   <div></div>
   <div></div>
...
</div>

#tbl_users tr:nth-child(even) {background: #CCC;}
#tbl_users tr:nth-child(odd) {background: #FFF;}

div#container div:nth-child(even) {background: #CCC;}
div#container div:nth-child(odd) {background: #FFF;}

#container div:nth-child(even) {background: #CCC;}
#container div:nth-child(odd) {background: #FFF;}

$('#container>div:odd').css("background-color", "#ff0000");
$('#container>div:even').css("background-color", "#00ff00");

#container div:nth-child(even) {background: #CCC;}
#container div:nth-child(odd) {background: #FFF;}