Uncover a div as you scroll down
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I'm trying to make it so when you scroll to the bottom of one div, it "uncovers" a div behind it. Here's an example of what I'm trying to accomplish: http://bergerfohr.com/profile/ (just scroll down a little bit).

I've been searching for a plugin to make this work to no avail. Does anyone know the best way to make this effect happen?