what’s the best way to add a class to the div with a class of post every 4 seconds using jquery? [closed]

var post_count = $('.post').length,
    current_index = 0;

setInterval(function(){

  $('.post').removeClass('display').eq(current_index).addClass('display');

  current_index++;

  if(current_index > post_count)
    current_index = 0; 

}, 4000);

Wrap it in a jQuery document.ready function 🙂