Fade Out A Div When Scroller Hits Bottom Of Another Div

This question sort of relates to this one: Append div to body when URL hash # changes I'm using Curtain.js and currently I have a fixed div that pops up when the hash changes. I.E

Solution 1:

you can use window.height() which returns the height of the browser's viewport:

var vp = $(window).height(); // height of the browser's viewport
var divs = $('.nav-wrap'); 
$(window).scroll(function(){
   if($(window).scrollTop() < vp){
         divs.fadeOut("slow");
   } else {
         divs.fadeIn("slow");
   }
});