jQuery cookie scroll position
@EthanBierlein Made a really good point, but he forgot something important.
It's always a good idea to wrap your code on an anonymous function:
(function ($) {
    $(document).ready(function () {
        [code]
    });
})(window.jQuery);

This prevents problems in case you run jQuery.noConflict() before, but you forget it.

You have the following code block:
$(window).scroll(function (event) {
    var scroll_positon = $(window).scrollTop();
    $.cookie('prev_scroll_position', scroll_positon, { expires: 7, path: '/' });
});

Instead of this, consider wrapping the $.cookie call in a setTimeout:
$(window).scroll(function (event) {
    var scroll_positon = $(window).scrollTop();
    setTimeout(function () {
        $.cookie('prev_scroll_position', scroll_positon, { expires: 7, path: '/' });
    }, 10);
});

This won't block the scroll event, which may improve UI responsiveness.
Why is that? The scroll event may be triggered multiple times a second, and that setTimeout schedules the cookie writting to a time that the browser is free.
Or that has some time for writing the cookie.
You should experiment with it.

Update!
As @Pevara pointed out in the comment section, this is not 100% a good idea.
He suggests to use a clearTimeout. From there, I could infer what he was trying to say.
Still follow the advice to use a setTimeout, but with a bigger delay (as he suggested: 250ms).
But now, the twist:
var timeout;
$(window).scroll(function (event) {
    var scroll_positon = $(window).scrollTop();
    
    clearTimeout(timeout); //clear it to avoid crazy writing
    
    //and create a new interval to write it later
    timeout = setTimeout(function () {
        $.cookie('prev_scroll_position', scroll_positon, { expires: 7, path: '/' });
    }, 250);
});

This will eliminate all the craziness of writing cookies like mad! And will write it only once, saving the browser from re-re-re-re-writing it.