(function($) {
	
	function calcParallax(tileheight, speedratio, scrollposition) {
		return (tileheight - (Math.floor(scrollposition / speedratio) % (tileheight+1)));
	}
	
	window.onscroll = function() {
		
		var posY = (document.documentElement.scrollTop) ? document.documentElement.scrollTop : window.pageYOffset;
		
		var plane = document.getElementById('taghover1');
		var planeparallax = calcParallax(2000, 1, posY);
		plane.style.backgroundPosition = "0 " + planeparallax + "px";

		
	}
	
})(jQuery);