// JavaScript Document
$(function() {   

		var theWindow = $(window),
		$bg = $("#bg"),
		aspectRatio = $bg.width() / $bg.height();
												
		function resizeBg() {
				
				if ( (theWindow.width() / theWindow.height()) < aspectRatio ) {
					$bg
						.removeClass()
						.addClass('bgheight');
				} else {
					$bg
						.removeClass()
						.addClass('bgwidth');
				}
										
		}
												
		theWindow.resize(function() {
				resizeBg();
		}).trigger("resize");

});