javascript - Using jquery to check if element has class constantly -

i'm using stickyjs create sticky header wordpress website. have enqueued scripts , sticky working perfectly.

what trying achieve check if nav element have set sticky has class called "is-sticky" , if change of css.

here code have already:

function stickyinit($) { $("#site-navigation").sticky({topspacing:0});  window.setinterval(check_sticky,500);  function check_sticky(){     if($("#site-navigation-sticky-wrapper").hasclass("is-sticky")){         console.log ("do something");     } } }  jquery(document).ready(function ($) { stickyinit($); }); 

this code in file have enqueued set nav sticky.

as can see have used setinterval try , create loop test "#site-navigation-sticky-wrapper" element see if has class mentioned above.

this code works , message in firebug console, ever once instead of repeatedly.

so question is, how test element see if has class "is-sticky" can alternate nav css when does?

also when class "is-sticky" isnt set on element (after have scrolled top) how set nav original position? or anyway?

check this fiddle - fires repeatedly when 'is-sticky' class active & nav position automatically restored former state when scroll stop.

// code function stickyinit($){      $("#site-navigation").sticky({topspacing:0});          function check_sticky(){             if ( $("#site-navigation-sticky-wrapper").hasclass("is-sticky") ) {                 console.log ("do something");             }         }      window.setinterval(check_sticky,500); }  jquery(document).ready(function ($) {      stickyinit($);  });