jquery autoscroll offset from top

Question

Ok, I rewrote thing for you and broke them down with full explination of all the moving parts. Although, with comments gone, you'll find this code much shorter than your own!

Example _{with comments}

//  the following establishes your own namespace, place everything about the scroll function in this namespace
var hlScroll = {
    //  properties
    buffer: 50, //  pixel buffer, positive is px above element, negative would move it so many pix below
    speed: 500, //  scroll speed, 1000 = 1second
    //  method
    scrollTo: function(e) {
        var gotoEle;    //  will be the element to find "top" too
        switch ($(this).attr('id')) {   //  same as an if else, but more visually sound on 2 strings in question
            case "next":    //  obviously go to next element
                //  filter is jquery function that allows us to get only certain elements in a collection
                //  here, our collection is ALL elements having class "highlight1"
                //  the filter method is kind of like .each, it goes through each element, the i means "index"
                //  in order for an element to stay in the collection, it must return true
                //  in this case, looking for "next", I see if current element's top is higher than window top + our buffer
                //  by including the buffer, I can make suer not to skip an element that might be "close" to the buffer but not over
                gotoEle = $('.highlight1').filter(function(i) { return $(this).offset().top > ($(window).scrollTop() + hlScroll.buffer) }).first();
                //  since we are getting next, we only want the first element returned, thus `.first()` will return just that!
                break;
            case "prev":
                //  a lil dif from above, here we look for the last element who's top is higher than the window
                gotoEle = $('.highlight1').filter(function(i) { return $(this).offset().top < $(window).scrollTop() }).last();
                break;
        }
        //  the if statement here keeps the scroll from firing if no element found
        //  if the element is found, we animate the page to scroll the element previously selected, - the buffer, keeping it so many pixels above the element (unless the buffer is negative)
        if (gotoEle.length) $("html, body").animate({ scrollTop: gotoEle.offset().top - hlScroll.buffer  }, hlScroll.speed);
        //  notice i selected "html, body". these are our main page elements which hold the page scroll
        //  you could adjust this in the future to scroll a parent container instead!
    }
}

$(function() {
    $("#next, #prev").on("click", hlScroll.scrollTo).click();
});

Example _{without comments}

var hlScroll = {
    buffer: 50,
    speed: 500,
    scrollTo: function(e) {
        var gotoEle;
        switch ($(this).attr('id')) {
            case "next":
                gotoEle = $('.highlight1').filter(function(i) { return $(this).offset().top > ($(window).scrollTop() + hlScroll.buffer) }).first();
                break;
            case "prev":
                gotoEle = $('.highlight1').filter(function(i) { return $(this).offset().top < $(window).scrollTop() }).last();
                break;
        }
        if (gotoEle.length) $("html, body").animate({ scrollTop: gotoEle.offset().top - hlScroll.buffer  }, hlScroll.speed);
    }
}

$(function() {
    $("#next, #prev").on("click", hlScroll.scrollTo).click();
});

jquery autoscroll offset from top

Example with comments

Example without comments

Example _{with comments}

Example _{without comments}