When to fetch more content on infinite scroll?
<p>I'm building out an infinite scrolling feature for my site and am debating at what scroll point to inject more content into the page. I've seen some that perform the request at a fixed pixel distance from the bottom of the document, and others that feel more percentage based. What do large sites like Tumblr, Facebook, Pinterest, etc. do? Are there different use cases between fixed pixel distance and percentage? Here's my code:</p>

<pre><code>// 20%
var scrollPoint = ($(document).height()/5);
if($(window).scrollTop() &gt;= $(document).height() - $(window).height() - scrollPoint) {
    console.log('Load more goodness');
}
</code></pre>

<p>Edit: On re-examining Facebook, it almost looks like they have a 'hot zone' where they pull in more content. If you use the mouse to scroll to the bottom you don't get an auto fetch of content.</p>
