snippet.js

var scrollToAnchor = function() {

        //cache some variables
        var scrollElement = 'html, body',
            $window = $(window);

        //grab all the anchor links
        $("a[href^='#']").click(function(e) {
            //stop immediate scroll
            e.preventDefault();
            //cache some variables
            var $this = $(this),
                //get the hash text
                target = this.hash,
                $target = $(target),
                //you can add or subtract from this value
                //to adjust the exact position
                scroll = $target.offset().top;
            //stop any current animation and then animate
            $(scrollElement).stop().animate({
                //scroll to the top of the id
                'scrollTop': scroll
            }, 500, 'swing', function() {
                //set the hash in the url bar
                window.location.hash = target;
                //reset the top again (jumps in FF/IE) if
                //you offset the scroll variable
                $window.scrollTop(scroll);
            });
        });
    }();