Some coffeescript syntax experimenting. How are these different?

gistfile1.txt

baz = -> alert 'baz'

foo -> alert 'foo'

bar ->
  foo
  baz = ->
    foo = -> alert 'new foo'
  baz()
  foo()

foo()
baz()

gistfile2.txt

var baz = function() {
  alert('baz');
}

function foo() {
  alert('foo');
}

function bar() {
  var foo;
  var baz = function() {
    foo = function() {
      alert('new foo');
    }
  }
  baz();
  foo();
}

foo()
baz();