$(function()
{
    function filterPath(string)
    {
        return string
            .replace(/^\//,'')
            .replace(/(index|default).[a-zA-Z]{3,4}$/,'')
            .replace(/\/$/,'');
    }

        var locationPath = filterPath(location.pathname);
        var scrollElem = scrollableElement('html', 'body');

        // Any links with hash tags in them (can't do ^= because of fully qualified URL potential)
        $('a[href*=#]').each(function()
        {
            // Ensure it's a same-page link
            var thisPath = filterPath(this.pathname) || locationPath;
            if(locationPath == thisPath
                && (location.hostname == this.hostname || !this.hostname)
                && this.hash.replace(/#/,''))
            {
                // Ensure target exists
                var $target = $(this.hash), target = this.hash;
    
                if($target.offset())
                {
                    // Find location of target
                    var targetOffset = $target.offset().top;
                    $(this).click(function(event)
                    {
                        removeActiveClass();

                        jQuery(this).addClass('active');
                        // Prevent jump-down
                        event.preventDefault();

                        // Animate to target
                        $(scrollElem).animate({scrollTop: targetOffset}, 400, function()
                        {
                            // Set hash in URL after animation successful
                            location.hash = target;
                        });
                    });
                }
            }
        });

        function removeActiveClass()
        {
            jQuery('a.active').each(function()
            {
                jQuery(this).removeClass('active');
            });
        }

        // Use the first element that is "scrollable"  (cross-browser fix?)
        function scrollableElement(els) {
                for (var i = 0, argLength = arguments.length; i <argLength; i++) {
                        var el = arguments[i],
                        $scrollElement = $(el);
                        if ($scrollElement.scrollTop()> 0) {
                                return el;
                        } else {
                                $scrollElement.scrollTop(1);
                                var isScrollable = $scrollElement.scrollTop()> 0;
                                $scrollElement.scrollTop(0);
                                if (isScrollable) {
                                        return el;
                                }
                        }
                }
                return [];
        }

});