You need to correct the errors in your HTML. If you open up IE's developer tools (press F12), you'll find an empty body
element; you've forgotten to open it after </head>
. View source and you'll find two html
elements being opened, too: you only need one.
Also, you don't need to reference html5.js if you're using Modernizr - it's built in.
(Credit to Gaby, who spotted all these mistakes too!)