$('#content').css( {backgroundPosition: "0 0"} )
             .animate(
                 {backgroundPosition:"(0 -900px)"}, 
                 {duration:500}
             );
	
$.fn.moveBackgroundY = function( pixels, duration, easing ) {

    return this.animate(
                { pixels: pixels },
                {
                    step: function(now,fx) {

                        console.log("Background Y position - " + now);

                        $(this).css({
                            backgroundPosition: '0px ' + now + 'px',
                        });
                    },
                    duration: duration,
                    complete: function() {
                        $(this).css({
                            backgroundPosition: '0px 0px',
                        });
                    }
                }, easing);
};
	
$('#content').moveBackgroundY(-900, 2100, 'easeInOutCubic');
	
$('#content').moveBackgroundY(300, 2100, 'easeInOutCubic');
	
return this.animate(
            { pixels: pixels },
            {
                step: function(now,fx) {
                    var calculatedPixels = this.pixels;
                    console.log("Background Y position - " + now);


                    $(this).css({
                        backgroundPosition: '0px ' + calculatedPixels + 'px',
                    });
                },
                duration: duration,
                complete: function() {
                    $(this).css({
                        backgroundPosition: '0px 0px',
                    });
                    //not so sure about this but you have to do this somehow
                    this.pixels = 0;
                }
            }, easing);