(function($) {
    $.fn.animatedBackground = function(options) {

    // build main options before element iteration by extending the default ones
    var opts = $.extend({}, $.fn.animatedBackground.defaults, options);

    function startAnimation() {
        $(this).stop().animate(
           {backgroundPosition:opts.backgroundPositionStart},
           {duration:opts.duration}
        );
    }

    function stopAnimation() {
        var animationConfig = { duration:opts.duration };
        if (opts.complete)
            animationConfig.complete = opts.complete;

        $(this).stop().animate(
            {backgroundPosition:opts.backgroundPositionEnd},
            animationConfig
        );
    }

    // for each side note, do the magic.
    return $(this)
        .css( {backgroundPosition: opts.backgroundPositionInit} )
        .mouseover(startAnimation)
        .mouseout(stopAnimation)
        .focus(startAnimation)
        .blur(stopAnimation)
    };

    // plugin defaults
    $.fn.animatedBackground.defaults = {
        backgroundPositionInit : "0 0",
        backgroundPositionStart : "(0 0)",
        backgroundPositionEnd : "(0 0)",
        durationStart : 500,
        durationEnd : 500,
        complete : null
    };
})(jQuery);