(function($) {
    $.fn.blink = function(options) {
        var defaults = { delay:500 };
        var options = $.extend(defaults, options);
        return this.each(function() {
            var obj = $(this);
            setInterval(function() {
                if($(obj).css("visibility") == "visible") {
                    $(obj).css('visibility','hidden');
                } else {
                    $(obj).css('visibility','visible');
                }
            }, options.delay);
        });
    }
}(jQuery))