FB setSize

<html>
<head>
</head>
<body>
<div id="fb-root"></div>
<script>
window.fbAsyncInit = function() {
    FB.init({appId: 'your app id', status: true, cookie: true,
             xfbml: true});
    FB.Canvas.setSize();
};

function sizeChangeCallback() {
    FB.Canvas.setSize();
}
(function() {
var e = document.createElement('script'); e.async = true;
e.src = document.location.protocol +
  '//connect.facebook.net/en_US/all.js';
document.getElementById('fb-root').appendChild(e);
}());
</script>
</body>
</html>