$(function() {

  $(window).resize(function() {
    var viewportWidth = $(window).width();
    var viewportHeight = $(window).height();
    if (viewportWidth < 1024 & viewportHeight < 768) {
      //do something here
    }
    else if (viewportWidth < 600 & viewportHeight < 400) {
      //do something here
    }
  });

});