when the page scroll to certain point, how to make a second fixed header appear
<p>I have a page that will be responsive and I also want to add a header that appears once the visitor scrolls for a bit. The header will supplant the main header in order to be visible as the user travels down the page. </p>

<p>I think this was a convention that people have used, and I need some help, as i can't really code it from scratch. </p>

<p>Has anyone seen examples or tutorials on this. I've looked but can't come up with it. </p>
