Gosh.. where to start..
There are few errors here..
Firstly you need to look at the code snippet I posted and use that. Hype will not understand the getElementsByClassName call. So you have to use document
The return value from the classname will be an Array not a element because it is getElements, plural
You will need to either specify which item in the array you want by index i.e
 indicates the first item
Or iterate over the array.
Next you do not need to specify a class by using the period ". " with the class name.
I.e should be
You normally only need to do that with jQuery
You are also missing the closing function bracket in the setFooter() function.
There may be more