$.fn.delay = function(time, callback){
    // Empty function:
    jQuery.fx.step.delay = function(){};
    // Return meaningless animation, (will be added to queue)
    return this.animate({delay:1}, time, callback);
}

$(document).ready(function(){
    $(".karta_button").click(function(){
        var page = $(this).attr("rel");

        $(".karta_button").removeClass("karta_active");

        $(this).addClass("karta_active");

        var margin_left = -558 * (page - 1);
        $("#img_container").animate({
        "marginLeft" : margin_left + "px"
        }, 300);

        return false;
    });   
        
});