Jquery fade in div as I scroll down

Question

I found this on another post and it works great except I need to reverse it so that when I scroll "down" it fades in the div.

var target = $('#bluOverlay');
var targetHeight = target.outerHeight();

$(document).scroll(function(e){
    var scrollPercent = (targetHeight - window.scrollY) / targetHeight;
    if(scrollPercent >= 0){
        target.css('opacity', scrollPercent);
    }
});

Here is the working fiddle from the other post http://jsfiddle.net/meEf4/

Answer 1

You can set the opacity of the div to zero initially and then when scrolled down increment the opacity gradually.

Demo

var target = $('div'),
  targetHeight = target.outerHeight();

$(document).scroll(function(e) {
  var scrollPercent = (targetHeight - window.scrollY) / targetHeight;

  if (scrollPercent >= 0) {
    target.css('opacity', 1 - scrollPercent);
  }
});

body {
  height: 3000px
}
div {
  height: 1000px;
  background: red;
  opacity: 0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.0/jquery.min.js"></script>
<div></div>