Javascript Puzzler

Invoking an anonymous JavaScript function is a handy technique for avoiding namespace collisions in JavaScript code. The following two code snippets show the definition of a top level function followed by the invocation of an anonymous function. One of them, however, has a (easily fixed) problem (at least on Firefox 3.0.8). Can you spot what it is? Try figuring it out without running the code - don't cheat! Put your answer in the comments.

Snippet one:

	function say(text) {
	alert(text);
	}
	(function() {
	var foo = "bar";
	})();

view raw gistfile1.js hosted with ❤ by GitHub

Snippet two:

	var say = function(text) {
	alert(text);
	}
	(function() {
	var foo = "bar";
	})();

view raw gistfile1.js hosted with ❤ by GitHub

Surprising behavior. I'd be interested to find out if different browsers / JavaScript engines treat these code snippets in the same way.