(function($) {
	$.fn.fullBg = function(){
		var bgImg = $(this);
		
		bgImg.addClass('fullBg');
		
		function resizeImg() {
			var imgwidth = bgImg.width();
			var imgheight = bgImg.height();
			
			var winwidth = $(window).width();
			var winheight = $(window).height();
			
			var widthratio = winwidth / imgwidth;
			var heightratio = winheight / imgheight;
			
			var widthdiff = heightratio * imgwidth;
			var heightdiff = widthratio * imgheight;
		
			if(heightdiff>winheight) {
				bgImg.css({
					width: winwidth+'px',
					height: heightdiff+'px'
				});
			} else {
				bgImg.css({
					width: widthdiff+'px',
					height: winheight+'px'
				});		
			}
		} 
		resizeImg();
		$(window).resize(function() {
			resizeImg();
		}); 
	};
})(jQuery)

jQuery(function($) {
	$("#background").fullBg();
});