Make a div appear when scrolling past a certain point of a page

Question

My goal is to make a fixed div appear at the top of a page once someone scrolls a certain amount of pixels down the page. Basically once the header section is out of view,

Answer 1

window.addEventListener("scroll",function() { 
   $('.fixedDiv')[(window.scrollY > 500)?"slideDown":"slideUp"]();
},false);

DEMO: http://jsfiddle.net/DerekL/8eG2A/

Answer 2

window.addEventListener("scroll",function() { 
   if(window.scrollY > 500) {
      $('.fixedDiv').slideDown();
   }
   else {
      $('.fixedDiv').slideUp();
   }
},false);

Answer 3

Brandon Tilley answered my question in a comment...

You would change the first line, with the startY, to be the specific Y position you need, rather than calculating based on the header's position and height. Here's an updated fiddle: jsfiddle.net/BinaryMuse/Ehney/1