How to get infinite scroll to work?

I'm trying to get this infinite load script to work in my project.

Here's my HTML:

<!-- Contents -->
<div id="page-container">
  <div id="scroller">
    <div id="page_1" class="pagina"></div>
    <div id="page_2" class="pagina"></div>
    <div id="page_3" class="pagina"></div>
    <div id="page_4" class="pagina"></div>
    <div id="page_5" class="pagina"></div>
    <div id="page_6" class="pagina"></div>
  </div>
</div>

<div id="pages-to-load">
  <div id="page_7" class="pagina"></div>
  ...
  <div id="page_25" class="pagina"></div>
</div>

And here's the script:

function scrollalert(){
  var pages = document.getElementById("scroller").getElementsByTagName("div");
  var currentPageId = pages[pages.length - 1];
  //console.log("currentPageId is: "+currentPageId);
  var scrollbox = document.querySelector('#page-container');
  var scrolltop = $(window).scrollTop();
  var scrollheight = scrollbox.scrollHeight;
  var windowheight = $(window).height();
  var scrolloffset=20;
  console.log(scrolltop);
  console.log(scrollheight);
  console.log(windowheight);
  console.log(scrollheight-(windowheight+scrolloffset));
  if(scrolltop>=(scrollheight-(windowheight+scrolloffset))) {
    //fetch new items
    console.log("loading more pages");

    (function() {
      alert('test');
      var i;
      var pagesToLoad = $("#pages-to-load > div").size();
      for (i = 0; i < pagesToLoad; i++) {
        console.log(pagesToLoad[i].id);
        $.get(pagesToLoad[i].id, function(newitems){
          alert('get new page');
          $('#scroller').append(newitems);
          updatestatus();
        })
      };
    })();
  };
}

Whatever I try, I can't seem to load and append my new pages. Also when scrolling down, my scrollTop and scrollHeight don't change. I'm sure I'm missing something obvious here. Also my pages-to-load is undefined?

Solution

Here is one infinite-scroll script of mine using JQuery which works:

Html:

<html>
    <head>
    <title>Scroll Troll Page</title>
    <script src="http://code.jquery.com/jquery-2.0.3.min.js"></script>
</head>
<body>
    <div id="scrollbox">
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
    </div>
</body>

<script type="text/javascript">
    $(window).scroll(function () {
        //- 10 = desired pixel distance from the bottom of the page while scrolling)
        if ($(window).scrollTop() >= $(document).height() - $(window).height() - 10) {
        var box = $("#scrollbox");
    //Just append some content here
    box.html(box.html() + "<br /><br /><br /><br /><br /><br /><br />");
        }
});
</script>

in Line:

box.html(box.html + "Place content to expand here");

You can add the content that should be added to your container when reaching the bottom of the page while scrolling.

Working jsFiddle:

http://jsfiddle.net/MdrJ4/3/