SO - changing style when scrolling

http://stackoverflow.com/q/8456590/1011582

HTML

<div id="wrap">
    <div id="column"></div>
</div>

CSS

#wrap {
    display: block;
    height: 400px;
    width: 400px;
    background-color: red;
}
#column {
    display: block;
    height: 20px;
    width: 20px;
    background-color: #bada55;
}

JavaScript

$(document).scroll(function() {
    $("#column").css("height", $(document).scrollTop() + 20);
});