jQuery(function($){ $(window).scroll(function() { if ($(document).scrollTop() > 50) { $('#section-padding').addClass('reduce-section-padding'); $('#row-width').addClass('increase-row-width'); } else { $('#section-padding').removeClass('reduce-section-padding'); $('#section-padding').addClass('slow-transition'); $('#row-width').removeClass('increase-row-width'); $('#row-width').addClass('slow-transition'); } }); });