var bar = new GalleryObject("bar",3920,980,980,true,5);function parallax(img_height,step,scrollpos){return(img_height-(Math.floor(scrollpos/step)%(img_height+1)));}window.onload=function(){window.onscroll=function(){var scrollY=(document.documentElement.scrollTop) ? document.documentElement.scrollTop : window.pageYOffset;var clouds=document.getElementById('clouds');var p=parallax(960,7.0,scrollY);clouds.style.backgroundPosition="0 "+ -p + "px";}}