Why my owl carousel not working

why my owl carousel not working

$(document).ready(function() {

  $("#owl-demo").owlCarousel({

    autoPlay: 3000, //Set AutoPlay to 3 seconds

    items: 4,
    itemsDesktop: [1199, 3],
    itemsDesktopSmall: [979, 3]

  });
}); // Notice there need to be two sets of closing brackets! One for the .ready and one for the carousel.